MyBatis学习总结（二）——MyBatis核心配置文件与输入输出映射
目录
- 一、MyBatis 配置文件概要
- 二、MyBatis 配置文件详解
- 三、使用接口 +XML 实现完整数据访问
- 3.1、在 IDEA 中创建一个 Maven 项目
- 3.2、添加依赖
- 3.3、创建 POJO 类
- 3.4、创建数据访问接口
- 3.5、根据接口编写 XML 映射器
- 3.6、添加 MyBatis 核心配置文件
- 3.7、编写 MyBatis 通用的工具类
- 3.8、通过 MyBatis 实现数据访问
- 3.9、测试用例
- 3.10、测试结果
- 四、MyBatis 输入输出映射
- 五、示例源代码
- 六、视频
- 七、作业
在上一章中我们学习了《MyBatis 学习总结（一）——ORM 概要与 MyBatis 快速起步》，这一章主要是介绍 MyBatis 核心配置文件、使用接口 +XML 实现完整数据访问、输入参数映射与输出结果映射等内容。
一、MyBatis 配置文件概要
MyBatis 核心配置文件在初始化时会被引用，在配置文件中定义了一些参数，当然可以完全不需要配置文件，全部通过编码实现，该配置文件主要是是起到解偶的作用。如第一讲中我们用到 conf.xml 文件：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="uchr@123"/> </dataSource> </environment> </environments> <mappers> <!--<mapper resource="mapper/studentMapper.xml"/>--> <mapper class="com.zhangguo.mybatis02.dao.StudentMapper"></mapper> </mappers> </configuration>
MyBatis 的配置文件包含了会深深影响 MyBatis 行为的设置（settings）和属性（properties）信息。文档的顶层结构如下：：
- configuration 配置
- properties 属性
- settings 设置
- typeAliases 类型别名
- typeHandlers 类型处理器
- objectFactory 对象工厂
- plugins 插件
- environments 环境
- environment 环境变量
- transactionManager 事务管理器
- dataSource 数据源
- environment 环境变量
- databaseIdProvider 数据库厂商标识
- mappers 映射器
二、MyBatis 配置文件详解
2.1、properties 属性
作用：将数据连接单独配置在 db.properties 中，只需要在 myBatisConfig.xml 中加载 db.properties 的属性值，在 myBatisConfig.xml 中就不需要对数据库连接参数进行硬编码。数据库连接参数只配置在 db.properties 中，方便对参数进行统一管理，其它 xml 可以引用该 db.properties。
db.properties 的内容：
##MySQL 连接字符串 #驱动 mysql.driver=com.mysql.jdbc.Driver #地址 mysql.url=jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&characterEncoding=UTF-8 #用户名 mysql.username=root #密码 mysql.password=uchr@123
在 myBatisConfig.xml 中加载 db.properties
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!--导入 db.properties 文件中的所有 key-value 数据--> <properties resource="db.properties"> <!--定义一个名称为 driver，值为 com.mysql.jdbc.Driver 的属性--> <property name="driver" value="com.mysql.jdbc.Driver"></property> </properties> <!--环境配置，default 为默认选择的环境--> <environments default="work"> <!--开发--> <environment id="development"> <!--事务管理--> <transactionManager type="JDBC"/> <!--连接池--> <dataSource type="POOLED"> <!--引用属性 ${mysql.driver}--> <property name="driver" value="${mysql.driver}"/> <property name="url" value="${mysql.url}"/> <property name="username" value="${mysql.username}"/> <property name="password" value="${mysql.password}"/> </dataSource> </environment> <!--运行--> <environment id="work"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&characterEncoding=UTF-8"/> <property name="username" value="root"/> <property name="password" value="uchr@123"/> </dataSource> </environment> </environments> <mappers> <!--<mapper resource="mapper/studentMapper.xml"/>--> <mapper class="com.zhangguo.mybatis02.dao.StudentMapper"></mapper> </mappers> </configuration>
properties 特性：
注意：
- 在 properties 元素体内定义的属性优先读取。
- 然后读取 properties 元素中 resource 或 url 加载的属性，它会覆盖已读取的同名属性。
- 最后读取 parameterType 传递的属性，它会覆盖已读取的同名属性
建议：
不要在 properties 元素体内添加任何属性值，只将属性值定义在 properties 文件中。
在 properties 文件中定义属性名要有一定的特殊性，如 xxxx.xxxx(jdbc.driver)
2.2、settings 全局参数配置
mybatis 框架运行时可以调整一些运行参数。比如，开启二级缓存，开启延迟加载等等。全局参数会影响 mybatis 的运行行为。
mybatis-settings 的配置属性以及描述
| setting(设置) | Description(描述) | valid Values(验证值组) | Default(默认值) |
| cacheEnabled | 在全局范围内启用或禁用缓存配置 任何映射器在此配置下。 | true | false | TRUE |
| lazyLoadingEnabled | 在全局范围内启用或禁用延迟加载。禁用时，所有相关联的将热加载。 | true | false | TRUE |
| aggressiveLazyLoading | 启用时，有延迟加载属性的对象将被完全加载后调用懒惰的任何属性。否则，每一个属性是按需加载。 | true | false | TRUE |
| multipleResultSetsEnabled | 允许或不允许从一个单独的语句（需要兼容的驱动程序）要返回多个结果集。 | true | false | TRUE |
| useColumnLabel | 使用列标签，而不是列名。在这方面，不同的驱动有不同的行为。参考驱动文档或测试两种方法来决定你的驱动程序的行为如何。 | true | false | TRUE |
| useGeneratedKeys | 允许 JDBC 支持生成的密钥。兼容的驱动程序是必需的。此设置强制生成的键被使用，如果设置为 true，一些驱动会不兼容性，但仍然可以工作。 | true | false | FALSE |
| autoMappingBehavior | 指定 MyBatis 的应如何自动映射列到字段 / 属性。NONE 自动映射。 PARTIAL 只会自动映射结果没有嵌套结果映射定义里面。 FULL 会自动映射的结果映射任何复杂的（包含嵌套或其他）。 |
NONE,PARTIAL,FULL |
PARTIAL |
| defaultExecutorType | 配置默认执行人。SIMPLE 执行人确实没有什么特别的。 REUSE 执行器重用准备好的语句。 BATCH 执行器重用语句和批处理更新。 |
SIMPLE,REUSE,BATCH |
SIMPLE |
| safeRowBoundsEnabled | 允许使用嵌套的语句 RowBounds。 | true | false | FALSE |
| mapUnderscoreToCamelCase | 从经典的数据库列名 A_COLUMN 启用自动映射到骆驼标识的经典的 Java 属性名 aColumn。 | true | false | FALSE |
| localCacheScope | MyBatis 的使用本地缓存，以防止循环引用，并加快反复嵌套查询。默认情况下（SESSION）会话期间执行的所有查询缓存。如果 localCacheScope=STATMENT 本地会话将被用于语句的执行，只是没有将数据共享之间的两个不同的调用相同的 SqlSession。 |
SESSION STATEMENT |
SESSION |
| dbcTypeForNull | 指定为空值时，没有特定的 JDBC 类型的参数的 JDBC 类型。有些驱动需要指定列的 JDBC 类型，但其他像 NULL，VARCHAR 或 OTHER 的工作与通用值。 | JdbcType enumeration. Most common are: NULL, VARCHAR and OTHER | OTHER |
| lazyLoadTriggerMethods | 指定触发延迟加载的对象的方法。 | A method name list separated by commas | equals,clone,hashCode,toString |
| defaultScriptingLanguage | 指定所使用的语言默认为动态 SQL 生成。 | A type alias or fully qualified class name. |
org.apache.ibatis.scripting.xmltags .XMLDynamicLanguageDriver |
| callSettersOnNulls | 指定如果 setter 方法或 map 的 put 方法时，将调用检索到的值是 null。它是有用的，当你依靠 Map.keySet（）或 null 初始化。注意（如整型，布尔等）不会被设置为 null。 | true | false | FALSE |
| logPrefix | 指定的前缀字串，MyBatis 将会增加记录器的名称。 | Any String | Not set |
| logImpl | 指定 MyBatis 的日志实现使用。如果此设置是不存在的记录的实施将自动查找。 | SLF4J | LOG4J | LOG4J2 | JDK_LOGGING | COMMONS_LOGGING | STDOUT_LOGGING | NO_LOGGING | Not set |
| proxyFactory | 指定代理工具，MyBatis 将会使用创建懒加载能力的对象。 | CGLIB | JAVASSIST | CGLIB |
官方文档 settings 的例子：
<setting name="cacheEnabled" value="true"/> <setting name="lazyLoadingEnabled" value="true"/> <setting name="multipleResultSetsEnabled" value="true"/> <setting name="useColumnLabel" value="true"/> <setting name="useGeneratedKeys" value="false"/> <setting name="autoMappingBehavior" value="PARTIAL"/> <setting name="defaultExecutorType" value="SIMPLE"/> <setting name="defaultStatementTimeout" value="25"/> <setting name="safeRowBoundsEnabled" value="false"/> <setting name="mapUnderscoreToCamelCase" value="false"/> <setting name="localCacheScope" value="SESSION"/> <setting name="jdbcTypeForNull" value="OTHER"/> <setting name="lazyLoadTriggerMethods" value="equals,clone,hashCode,toString"/> </settings>
示例：
这里设置 MyBatis 的日志输出到控制台：
<!--外部引入的内容将覆盖内部定义的--> <properties resource="db.properties"> <!--定义一个名称为 driver，值为 com.mysql.jdbc.Driver 的属性--> <property name="mysql.driver" value="com.mysql.jdbc.Driver"></property> </properties><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置是否允许缓存</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="cacheEnabled"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="true"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置日志输出的目标</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="logImpl"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="STDOUT_LOGGING"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span></pre>
结果：
2.3、typeAiases(别名)
在mapper.xml中，定义很多的statement，statement需要parameterType指定输入参数的类型、需要resultType指定输出结果的映射类型。
如果在指定类型时输入类型全路径，不方便进行开发，可以针对parameterType或resultType指定的类型定义一些别名，在mapper.xml中通过别名定义，方便开发。
如下所示类型 com.zhangguo.mybatis02.entities.Student 会反复出现，冗余：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.zhangguo.mybatis02.mapper.studentMapper"> <select id="selectStudentById" resultType="com.zhangguo.mybatis02.entities.Student"> SELECT id,name,sex from student where id=#{id} </select><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByName"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.entities.Student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where name like '%${value}%'; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">insert </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="insertStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.entities.Student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> insert into student(name,sex) VALUES(#{name},'${sex}') </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">insert</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">update </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="updateStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.entities.Student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> update student set name=#{name},sex=#{sex} where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">update</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">delete </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="deleteStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="int"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> delete from student where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">></span></mapper>
2.3.1.MyBatis 默认支持的别名
|
别名 |
映射的类型 |
|
_byte |
byte |
|
_long |
long |
|
_short |
short |
|
_int |
int |
|
_integer |
int |
|
_double |
double |
|
_float |
float |
|
_boolean |
boolean |
|
string |
String |
|
byte |
Byte |
|
long |
Long |
|
short |
Short |
|
int |
Integer |
|
integer |
Integer |
|
double |
Double |
|
float |
Float |
|
boolean |
Boolean |
|
date |
Date |
|
decimal |
BigDecimal |
|
bigdecimal |
BigDecimal |
2.3.2. 自定义别名
（一）、单个别名定义 (在 myBatisConfig.xml)
<settings> <!--设置是否允许缓存--> <setting name="cacheEnabled" value="true"/> <!--设置日志输出的目标--> <setting name="logImpl" value="STDOUT_LOGGING"/> </settings><span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">别名</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span><!--定义单个别名，指定名称为 student，对应的类型为 com.zhangguo.mybatis02.entities.Student-->
<typeAlias type="com.zhangguo.mybatis02.entities.Student" alias="student"></typeAlias>
</typeAliases>
UserMapper.xml 引用别名
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.zhangguo.mybatis02.mapper.studentMapper"> <select id="selectStudentById" resultType="student"> SELECT id,name,sex from student where id=#{id} </select><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByName"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><strong> resultType<span style="color: rgba(0, 0, 255, 1)">="student"</span></strong><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where name like '%${value}%'; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">insert </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="insertStudent"</span><strong><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span></strong><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> insert into student(name,sex) VALUES(#{name},'${sex}') </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">insert</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">update </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="updateStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> update student set name=#{name},sex=#{sex} where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">update</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">delete </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="deleteStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="int"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> delete from student where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">></span></mapper>
（二）批量定义别名，扫描指定的包
定义单个别名的缺点很明显，如果项目中有很多别名则需要一个一个定义，且修改类型了还要修改配置文件非常麻烦，可以指定一个包，将下面所有的类都按照一定的规则定义成别名：
<settings> <!--设置是否允许缓存--> <setting name="cacheEnabled" value="true"/> <!--设置日志输出的目标--> <setting name="logImpl" value="STDOUT_LOGGING"/> </settings><span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">别名</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">定义单个别名，指定名称为student，对应的类型为com.zhangguo.mybatis02.entities.Student</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><typeAlias type="com.zhangguo.mybatis02.entities.Student" alias="student"></typeAlias></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">指定包名下所有的类被自动扫描并定义默认别名， mybatis会自动扫描包中的pojo类，自动定义别名，别名就是类名(首字母大写或小写都可以)</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">package </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.entities"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">package</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span></pre>
如果 com.zhangguo.mybatis02.entities 包下有一个名为 Student 的类，则使用别名时可以是：student，或 Student。
你一定会想到当两个名称相同时的冲突问题，可以使用注解解决
解决方法：
2.4、typeHandlers(类型处理器)
mybatis中通过typeHandlers完成jdbc类型和java类型的转换。
通常情况下，mybatis提供的类型处理器满足日常需要，不需要自定义.
mybatis支持类型处理器：
|
类型处理器 |
Java 类型 |
JDBC 类型 |
|
BooleanTypeHandler |
Boolean，boolean |
任何兼容的布尔值 |
|
ByteTypeHandler |
Byte，byte |
任何兼容的数字或字节类型 |
|
ShortTypeHandler |
Short，short |
任何兼容的数字或短整型 |
|
IntegerTypeHandler |
Integer，int |
任何兼容的数字和整型 |
|
LongTypeHandler |
Long，long |
任何兼容的数字或长整型 |
|
FloatTypeHandler |
Float，float |
任何兼容的数字或单精度浮点型 |
|
DoubleTypeHandler |
Double，double |
任何兼容的数字或双精度浮点型 |
|
BigDecimalTypeHandler |
BigDecimal |
任何兼容的数字或十进制小数类型 |
|
StringTypeHandler |
String |
CHAR 和 VARCHAR 类型 |
|
ClobTypeHandler |
String |
CLOB 和 LONGVARCHAR 类型 |
|
NStringTypeHandler |
String |
NVARCHAR 和 NCHAR 类型 |
|
NClobTypeHandler |
String |
NCLOB 类型 |
|
ByteArrayTypeHandler |
byte[] |
任何兼容的字节流类型 |
|
BlobTypeHandler |
byte[] |
BLOB 和 LONGVARBINARY 类型 |
|
DateTypeHandler |
Date（java.util） |
TIMESTAMP 类型 |
|
DateOnlyTypeHandler |
Date（java.util） |
DATE 类型 |
|
TimeOnlyTypeHandler |
Date（java.util） |
TIME 类型 |
|
SqlTimestampTypeHandler |
Timestamp（java.sql） |
TIMESTAMP 类型 |
|
SqlDateTypeHandler |
Date（java.sql） |
DATE 类型 |
|
SqlTimeTypeHandler |
Time（java.sql） |
TIME 类型 |
|
ObjectTypeHandler |
任意 |
其他或未指定类型 |
|
EnumTypeHandler |
Enumeration 类型 |
VARCHAR- 任何兼容的字符串类型，作为代码存储（而不是索引）。 |
2.5、mappers(映射配置)
映射配置可以有多种方式，如下 XML 配置所示：
<!-- 将 sql 映射注册到全局配置中--> <mappers><span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> mapper 单个注册（mapper如果多的话，不太可能用这种方式） resource：引用类路径下的文件 url：引用磁盘路径下的资源 class，引用接口 package 批量注册（基本上使用这种方式） name：mapper接口与mapper.xml所在的包名 </span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> 第一种：注册sql映射文件</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">resource</span><span style="color: rgba(0, 0, 255, 1)">="com/zhangguo/mapper/UserMapper.xml"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> 第二种：注册接口sql映射文件必须与接口同名，并且放在同一目录下</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">class</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mapper.UserMapper"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> 第三种：注册基于注解的接口 基于注解 没有sql映射文件，所有的sql都是利用注解写在接口上</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">class</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mapper.TeacherMapper"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> 第四种：批量注册 需要将sql配置文件和接口放到同一目录下</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">package </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mapper"</span> <span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">></span></pre>
2.5.1、通过 resource 加载单个映射文件
<mappers> <!--根据路径注册一个基于 XML 的映射器--> <mapper resource="mapper/studentMapper.xml"/> </mappers>
注意位置
2.5.2: 通过 mapper 接口加载单个映射文件
<!-- 通过 mapper 接口加载单个映射配置文件 遵循一定的规范：需要将 mapper 接口类名和 mapper.xml 映射文件名称保持一致，且在一个目录中； 上边规范的前提是：使用的是 mapper 代理方法; --> <mapper class="com.mybatis.mapper.UserMapper"/>
按照上边的规范，将mapper.java和mapper.xml放在一个目录 ，且同名。
注意：
对于 Maven 项目，IntelliJ IDEA 默认是不处理 src/main/java 中的非 java 文件的，不专门在 pom.xml 中配置 <resources> 是会报错的，参考处理办法：
<resources> <resource> <directory>src/main/java</directory> <includes> <include>**/*.properties</include> <include>**/*.xml</include> </includes> <filtering>true</filtering> </resource> <resource> <directory>src/main/resources</directory> <includes> <include>**/*.properties</include> <include>**/*.xml</include> </includes> <filtering>true</filtering> </resource> </resources>
所以 src/main/java 中最好不要出现非 java 文件。实际上，将 mapper.xml 放在 src/main/resources 中比较合适。
2.5.3、批量加载 mapper
<!-- 批量加载映射配置文件,mybatis 自动扫描包下面的 mapper 接口进行加载 遵循一定的规范：需要将 mapper 接口类名和 mapper.xml 映射文件名称保持一致，且在一个目录中； 上边规范的前提是：使用的是 mapper 代理方法; --> <package name="com.mybatis.mapper"/>
最后的配置文件：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!--导入 db.properties 文件中的所有 key-value 数据--> <!--外部引入的内容将覆盖内部定义的--> <properties resource="db.properties"> <!--定义一个名称为 driver，值为 com.mysql.jdbc.Driver 的属性--> <property name="mysql.driver" value="com.mysql.jdbc.Driver"></property> </properties><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置是否允许缓存</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="cacheEnabled"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="true"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置日志输出的目标</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="logImpl"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="STDOUT_LOGGING"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">别名</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">定义单个别名，指定名称为student，对应的类型为com.zhangguo.mybatis02.entities.Student</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><typeAlias type="com.zhangguo.mybatis02.entities.Student" alias="student"></typeAlias></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">指定包名下所有的类被自动扫描并定义默认别名， mybatis会自动扫描包中的pojo类，自动定义别名，别名就是类名(首字母大写或小写都可以)</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">package </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.entities"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">package</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">注册自定义的类型处理器</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeHandlers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><typeHandler handler="" javaType="" jdbcType=""></typeHandler></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">typeHandlers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">环境配置，default为默认选择的环境</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environments </span><span style="color: rgba(255, 0, 0, 1)">default</span><span style="color: rgba(0, 0, 255, 1)">="development"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">开发</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environment </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="development"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">事务管理</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">transactionManager </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="JDBC"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">连接池</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dataSource </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="POOLED"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">引用属性${mysql.driver}</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="driver"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.driver}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="url"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.url}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="username"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.username}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="password"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.password}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dataSource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environment</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">运行</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environment </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="work"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">transactionManager </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="JDBC"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dataSource </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="POOLED"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="driver"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${driver}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="url"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&amp;characterEncoding=UTF-8"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="username"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="root"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="password"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="uchr@123"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dataSource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environment</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environments</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">根据路径注册一个基于XML的映射器</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">resource</span><span style="color: rgba(0, 0, 255, 1)">="mapper/studentMapper.xml"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">根据类型注册一个基于注解的映射器，接口</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">class</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.dao.StudentMapper"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">mapper</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">根据包名批量注册包下所有基于注解的映射器</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">package </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis02.dao"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">package</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">></span></configuration>
三、使用接口 +XML 实现完整数据访问
上一章中使用 XML 作为映射器与使用接口加注解的形式分别实现了完整的数据访问，可以点击《MyBatis 学习总结（一）——ORM 概要与 MyBatis 快速起步》查看，这里综合两种方式实现数据访问，各取所长，配置灵活，在代码中不需要引用很长的 id 名称，面向接口编程，示例如下：
3.1、在 IDEA 中创建一个 Maven 项目
创建成功的目录结构如下：
3.2、添加依赖
pom.xml 文件如下：
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>com.zhangguo.mybatis03<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>MyBatis03<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>1.0-SNAPSHOT<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependencies</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">MyBatis </span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>org.mybatis<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>mybatis<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>3.4.6<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">MySql数据库驱动 </span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>mysql<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>mysql-connector-java<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>5.1.38<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"> JUnit单元测试工具 </span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span>junit<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">groupId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span>junit<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">artifactId</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span>4.11<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">version</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">scope</span><span style="color: rgba(0, 0, 255, 1)">></span>test<span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">scope</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dependencies</span><span style="color: rgba(0, 0, 255, 1)">></span></project>
添加成功效果如下：
3.3、创建 POJO 类
学生 POJO 类如下：
package com.zhangguo.mybatis03.entities;/**
学生实体
*/
public class Student {
private int id;
private String name;
private String sex;public int getId() {
return id;
}public void setId(int id) {
this.id = id;
}public String getName() {
return name;
}public void setName(String name) {
this.name = name;
}public String getSex() {
return sex;
}public void setSex(String sex) {
this.sex = sex;
}@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='"+ name +''' +
", sex='"+ sex +''' +
'}';
}
}
3.4、创建数据访问接口
StudentMapper.java：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Student;
import java.util.List;
public interface StudentMapper {
/**
* 根据学生编号获得学生对象
*/
Student selectStudentById(int id);</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Student><span style="color: rgba(0, 0, 0, 1)"> selectStudentsByName(String name); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 添加学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> insertStudent(Student entity); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 更新学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> updateStudent(Student entity); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudent(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id);}
3.5、根据接口编写 XML 映射器
要求方法名与 Id 同名，包名与 namespace 同名。
在 src/main/resources/mapper 目录下创建 studentMapper.xml 文件，内容如下：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.zhangguo.mybatis03.dao.StudentMapper"> <select id="selectStudentById" resultType="Student"> SELECT id,name,sex from student where id=#{id} </select><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByName"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where name like '%${value}%'; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">insert </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="insertStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> insert into student(name,sex) VALUES(#{name},'${sex}') </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">insert</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">update </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="updateStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> update student set name=#{name},sex=#{sex} where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">update</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">delete </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="deleteStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="int"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> delete from student where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">></span></mapper>
3.6、添加 MyBatis 核心配置文件
在 src/main/resources 目录下创建两个配置文件。
mybatisCfg.xml 文件如下：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!--导入 db.properties 文件中的所有 key-value 数据--> <!--外部引入的内容将覆盖内部定义的--> <properties resource="db.properties"> <!--定义一个名称为 driver，值为 com.mysql.jdbc.Driver 的属性--> <property name="mysql.driver" value="com.mysql.jdbc.Driver"></property> </properties><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置是否允许缓存</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="cacheEnabled"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="true"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">设置日志输出的目标</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">setting </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="logImpl"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="STDOUT_LOGGING"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">settings</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">别名</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">定义单个别名，指定名称为student，对应的类型为com.zhangguo.mybatis02.entities.Student</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><typeAlias type="com.zhangguo.mybatis02.entities.Student" alias="student"></typeAlias></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">指定包名下所有的类被自动扫描并定义默认别名， mybatis会自动扫描包中的pojo类，自动定义别名，别名就是类名(首字母大写或小写都可以)</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">package </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="com.zhangguo.mybatis03.entities"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">package</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">typeAliases</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">注册自定义的类型处理器</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">typeHandlers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><typeHandler handler="" javaType="" jdbcType=""></typeHandler></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">typeHandlers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">环境配置，default为默认选择的环境</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environments </span><span style="color: rgba(255, 0, 0, 1)">default</span><span style="color: rgba(0, 0, 255, 1)">="development"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">开发</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environment </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="development"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">事务管理</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">transactionManager </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="JDBC"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">连接池</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dataSource </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="POOLED"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">引用属性${mysql.driver}</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="driver"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.driver}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="url"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.url}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="username"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.username}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="password"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${mysql.password}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dataSource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environment</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">运行</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">environment </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="work"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">transactionManager </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="JDBC"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">dataSource </span><span style="color: rgba(255, 0, 0, 1)">type</span><span style="color: rgba(0, 0, 255, 1)">="POOLED"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="driver"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="${driver}"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="url"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&amp;characterEncoding=UTF-8"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="username"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="root"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">property </span><span style="color: rgba(255, 0, 0, 1)">name</span><span style="color: rgba(0, 0, 255, 1)">="password"</span><span style="color: rgba(255, 0, 0, 1)"> value</span><span style="color: rgba(0, 0, 255, 1)">="uchr@123"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">dataSource</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environment</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">environments</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">根据路径注册一个基于XML的映射器</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">mapper </span><span style="color: rgba(255, 0, 0, 1)">resource</span><span style="color: rgba(0, 0, 255, 1)">="mapper/studentMapper.xml"</span><span style="color: rgba(0, 0, 255, 1)">/></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">></span></configuration>
db.properties 文件内容如下：
##MySQL 连接字符串 #驱动 mysql.driver=com.mysql.jdbc.Driver #地址 mysql.url=jdbc:mysql://127.0.0.1:3306/nfmall?useUnicode=true&characterEncoding=UTF-8 #用户名 mysql.username=root #密码 mysql.password=uchr@123
3.7、编写 MyBatis 通用的工具类
SqlSessionFactoryUtil.java 内容如下：
package com.zhangguo.mybatis03.utils;import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.IOException;
import java.io.InputStream;/**
MyBatis 会话工具类
*/
public class SqlSessionFactoryUtil {/**
获得会话工厂
*/
public static SqlSessionFactory getFactory(){
InputStream inputStream = null;
SqlSessionFactory sqlSessionFactory=null;
try{
//加载 mybatisCfg.xml 配置文件，转换成输入流
inputStream = SqlSessionFactoryUtil.class.getClassLoader().getResourceAsStream("mybatisCfg.xml");</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">根据配置文件的输入流构造一个SQL会话工厂</span> sqlSessionFactory = <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> SqlSessionFactoryBuilder().build(inputStream);}
finally {
if(inputStream!=null){
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sqlSessionFactory;
}/**
- 获得 sql 会话，是否自动提交
- */
public static SqlSession openSession(boolean isAutoCommit){
return getFactory().openSession(isAutoCommit);
}/**
- 关闭会话
- */
public static void closeSession(SqlSession session){
if(session!=null){
session.close();
}
}}
3.8、通过 MyBatis 实现数据访问
StudentDao.java 内容如下：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Student;
import com.zhangguo.mybatis03.utils.SqlSessionFactoryUtil;
import org.apache.ibatis.session.SqlSession;import java.util.List;
public class StudentDao implements StudentMapper {
</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生编号获得学生对象 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> Student selectStudentById(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id) { Student entity </span>= <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper=session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询单个对象，指定参数为3</span> entity =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentById(id); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> entity; } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Student><span style="color: rgba(0, 0, 0, 1)"> selectStudentsByName(String name) { List</span><Student> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper=session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)">mapper.selectStudentsByName(name); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 添加学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> insertStudent(Student entity) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows=0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper=session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行添加</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.insertStudent(entity); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 更新学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> updateStudent(Student entity) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows=0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper=session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行更新</span> rows =<span style="color: rgba(0, 0, 0, 1)">mapper.updateStudent(entity); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudent(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows=0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper=session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行删除</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.deleteStudent(id); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}}
最后完成的项目结构：
3.9、测试用例
在测试类上添加注解 @FixMethodOrder(MethodSorters.JVM) 的目的是指定测试方法按定义的顺序执行。
StudentDaoTest.java 如下所示：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Student;
import org.junit.*;
import org.junit.runners.MethodSorters;import java.util.List;
/**
StudentDao Tester.
@author <Authors name>
@version 1.0
@since <pre>09/26/2018</pre>
*/
@FixMethodOrder(MethodSorters.JVM)//指定测试方法按定义的顺序执行
public class StudentDaoTest {
StudentMapper dao;
@Before
public void before() throws Exception {
dao=new StudentDao();
}@After
public void after() throws Exception {
}/**
- Method: selectStudentById(int id)
*/
@Test
public void testSelectStudentById() throws Exception {
Student entity=dao.selectStudentById(1);
System.out.println(entity);
Assert.assertNotNull(entity);
}/**
- Method: selectStudentsByName(String name)
*/
@Test
public void testSelectStudentsByName() throws Exception {
List<Student> students=dao.selectStudentsByName("C");
System.out.println(students);
Assert.assertNotNull(students);
}/**
Method: insertStudent
*/
@Test
public void testInsertStudent() throws Exception {
Student entity=new Student();
entity.setName("张大");
entity.setSex("boy");Assert.assertEquals(1,dao.insertStudent(entity));
}/**
Method: updateStudent
*/
@Test
public void testUpdateStudent() throws Exception {
Student entity=dao.selectStudentById(11);
entity.setName("张丽美");
entity.setSex("girl");Assert.assertEquals(1,dao.updateStudent(entity));
}/**
- Method: deleteStudent
*/
@Test
public void testDeleteStudent() throws Exception {
Assert.assertEquals(1,dao.deleteStudent(12));
}
}
3.10、测试结果
测试前的数据库：
测试结果：
日志：
"C:\Program Files\Java\jdk1.8.0_111\bin\java" -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2017.2.1\lib\idea_rt.jar=2783:C:\Program Files\JetBrains\IntelliJ IDEA 2017.2.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\JetBrains\IntelliJ IDEA 2017.2.1\lib\idea_rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2017.2.1\plugins\junit\lib\junit-rt.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2017.2.1\plugins\junit\lib\junit5-rt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_111\jre\lib\rt.jar;D:\Documents\Downloads\Compressed\MyBatis03\target\test-classes;D:\Documents\Downloads\Compressed\MyBatis03\target\classes;C:\Users\Administrator\.m2\repository\org\mybatis\mybatis\3.4.6\mybatis-3.4.6.jar;C:\Users\Administrator\.m2\repository\mysql\mysql-connector-java\5.1.38\mysql-connector-java-5.1.38.jar;C:\Users\Administrator\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\Administrator\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 com.zhangguo.mybatis03.dao.StudentDaoTest Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 662822946. ==> Preparing: delete from student where id=? ==> Parameters: 12(Integer) <== Updates: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@2781e022] Returned connection 662822946 to pool. Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 1045941616. ==> Preparing: SELECT id,name,sex from student where id=? ==> Parameters: 11(Integer) <== Columns: id, name, sex <== Row: 11, lili, secret <== Total: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@3e57cd70] Returned connection 1045941616 to pool. Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 1540270363. ==> Preparing: update student set name=?,sex=? where id=? ==> Parameters: 张丽美 (String), girl(String), 11(Integer) <== Updates: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@5bcea91b] Returned connection 1540270363 to pool. Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 681384962. ==> Preparing: insert into student(name,sex) VALUES(?,'boy') ==> Parameters: 张大 (String) <== Updates: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@289d1c02] Returned connection 681384962 to pool. Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 428910174. ==> Preparing: SELECT id,name,sex from student where name like '%C%'; ==> Parameters: <== Columns: id, name, sex <== Row: 4, candy, secret <== Total: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@1990a65e] Returned connection 428910174 to pool. [Student{id=4, name='candy', sex='secret'}] Logging initialized using 'class org.apache.ibatis.logging.stdout.StdOutImpl' adapter. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. PooledDataSource forcefully closed/removed all connections. Opening JDBC Connection Created connection 1134612201. ==> Preparing: SELECT id,name,sex from student where id=? ==> Parameters: 1(Integer) <== Columns: id, name, sex <== Row: 1, rose, girl <== Total: 1 Closing JDBC Connection [com.mysql.jdbc.JDBC4Connection@43a0cee9] Returned connection 1134612201 to pool. Student{id=1, name='rose', sex='girl'}Process finished with exit code 0
测试后的数据库：
四、MyBatis 输入输出映射
4.1、输入映射
通过 parameterType 指定输入参数的类型，类型可以是简单类型、HashMap、POJO的包装类型。
Mybatis 的配置文件中的 select,insert,update,delete 有一个属性 parameter 来接收 mapper 接口方法中的参数。可以接收的类型有简单类型和复杂类型，但是只能是一个参数。这个属性是可选的，因为 Mybatis 可以通过 TypeHandler 来判断传入的参数类型，默认值是 unset。
4.1.1、基本类型
各种 java 的基本数据类型。常用的有 int、String、Data 等
接口：
/** * 根据学生编号获得学生对象 */ Student selectStudentById(int id);
映射：
<select id="selectStudentById" resultType="Student" parameterType="int"> SELECT id,name,sex from student where id=#{id} </select>
测试：
/** * Method: selectStudentById(int id) */ @Test public void testSelectStudentById() throws Exception { Student entity=dao.selectStudentById(1); System.out.println(entity); Assert.assertNotNull(entity); }
结果：
用 #{变量名} 来取值，这里的变量名是任意的，可以用 value 或者是其它的什么值，这里用 id 是为了便于理解，并不存在什么对应关系的。因为 java 反射主只能够得到方法参数的类型，而无从知道参数的名字的。当在动态 sql 中的 if 语句中的 test 传递参数时，就必须要用 _parameter 来传递参数了（OGNL 表达式），如果你传入 id 就会报错。
4.1.2、多个参数
（一）、旧版本 MyBatis 使用索引号：
<select id="selectStudentsByNameOrSex" resultType="student"> SELECT id,name,sex from student where name='%${0}%' or sex=#{1}; </select>由于是多参数那么就不能使用 parameterType， 改用 #｛index｝是第几个就用第几个的索引，索引从 0 开始
注意：
如果出现错误：Parameter '0' not found. Available parameters are [arg1, arg0, param1, param2]，请使用 #{arg0} 或 #{param1}
注意：在 MyBatis3.4.4 版以后不能直接使用 #{0} 要使用 #{arg0}
（二）、新版本 MyBatis 使用索引号：
接口：
/** * 根据学生姓名或性别获得学生集合 */ List<Student> selectStudentsByNameOrSex(String name,String sex);
映射：
<select id="selectStudentsByNameOrSex" resultType="student"> SELECT id,name,sex from student where name like '%${arg0}%' or sex=#{param2}; </select>方法一：arg0,arg1,arg2...
方法二：param1,param2,param3...
测试：
/** * Method: selectStudentsByNameOrSex(String name, String sex) */ @Test public void selectStudentsByNameOrSex() throws Exception { List<Student> students=dao.selectStudentsByNameOrSex("Candy","boy"); System.out.println(students); Assert.assertNotNull(students); }
结果：
（三）、使用 Map
接口：
/** * 根据学生姓名或性别获得学生集合 */ List<Student> selectStudentsByNameOrSex(Map<String,Object> params);
映射：
<select id="selectStudentsByNameOrSex" resultType="student"> SELECT id,name,sex from student where name like '%${name}%' or sex=#{sex}; </select>
测试：
/** * Method: List<Student> selectStudentsByNameOrSex(Map<String,Object> params); */ @Test public void selectStudentsByNameOrSex() throws Exception { Map<String,Object> params=new HashMap<String,Object>(); params.put("name","Candy"); params.put("sex","girl"); List<Student> students=dao.selectStudentsByNameOrSex(params);System.out.println(students); Assert.assertNotNull(students); }</span></pre>
结果：
（四）、注解参数名称：
接口：
/** * 根据学生姓名或性别获得学生集合 */ List<Student> selectStudentsByNameOrSex(@Param("realname") String name,@Param("sex") String sex);
映射：
<select id="selectStudentsByNameOrSex" resultType="student"> SELECT id,name,sex from student where name like '%${realname}%' or sex=#{sex}; </select>
测试：
/** * Method: selectStudentsByNameOrSex(String name,String sex) */ @Test public void testSelectStudentsByNameOrSex() throws Exception { List<Student> students=dao.selectStudentsByNameOrSex("C","boy"); System.out.println(students); Assert.assertNotNull(students); }
结果：
4.1.3、POJO 对象
各种类型的 POJO，取值用 #{属性名}。这里的属性名是和传入的 POJO 中的属性名一一对应。
接口：
/** * 添加学生 */ int insertStudent(Student entity);
映射：
<insert id="insertStudent" parameterType="student"> insert into student(name,sex) VALUES(#{name},'${sex}') </insert>
测试：
/** * Method: insertStudent */ @Test public void testInsertStudent() throws Exception { Student entity=new Student(); entity.setName("张明"); entity.setSex("boy");Assert.assertEquals(</span>1<span style="color: rgba(0, 0, 0, 1)">,dao.insertStudent(entity)); }</span></pre>
结果：
如果要在 if 元素中测试传入的 user 参数, 仍然要使用 _parameter 来引用传递进来的实际参数, 因为传递进来的 User 对象的名字是不可考的。如果测试对象的属性, 则直接引用属性名字就可以了。
测试 user 对象:
<if test="_parameter!= null">
测试 user 对象的属性:
<if test="name!= null">
如果对象中还存在对象则需要使用 ${属性名. 属性.x} 方式访问
4.1.4、Map
具体请查看 4.1.2 节。
传入 map 类型, 直接通过 #{keyname} 就可以引用到键对应的值。使用 @param 注释的多个参数值也会组装成一个 map 数据结构, 和直接传递 map 进来没有区别。
mapper 接口:
int updateByExample(@Param("user") User user, @Param("example") UserExample example);
sql 映射:
<update id="updateByExample" parameterType="map" >update tb_user set id = #{user.id}, ...
<if test="_parameter != null" >
<include refid="Update_By_Example_Where_Clause" />
</if>
</update>
注意这里测试传递进来的 map 是否为空, 仍然使用 _parameter
4.1.5、集合类型
可以传递一个 List 或 Array 类型的对象作为参数,MyBatis 会自动的将 List 或 Array 对象包装到一个 Map 对象中,List 类型对象会使用 list 作为键名, 而 Array 对象会用 array 作为键名。集合类型通常用于构造 IN 条件，sql 映射文件中使用 foreach 元素来遍历 List 或 Array 元素。
假定这里需要实现多删除功能，示例如下：
接口：
/** * 删除多个学生通过编号 */ int deleteStudents(List<Integer> ids);
映射：
<delete id="deleteStudents"> delete from student where id in <foreach collection="list" item="id" open="(" separator="," close=")"> #{id} </foreach> </delete>
collection 这里只能是 list
测试：
/** * Method: deleteStudents */ @Test public void testDeleteStudents() throws Exception { List<Integer> ids=new ArrayList<Integer>(); ids.add(10); ids.add(11); Assert.assertEquals(2,dao.deleteStudents(ids)); }
结果：
当然查询中也可以这样使用
public List<XXXBean> getXXXBeanList(List<String> list);<select id="getXXXBeanList" resultType="XXBean">
select 字段... from XXX where id in
<foreach item="item" index="index" collection="list" open="(" separator="," close=")">
#{item}
</foreach>
</select>foreach 最后的效果是 select 字段... from XXX where id in ('1','2','3','4')
对于单独传递的 List 或 Array, 在 SQL 映射文件中映射时, 只能通过 list 或 array 来引用。但是如果对象类型有属性的类型为 List 或 Array，则在 sql 映射文件的 foreach 元素中, 可以直接使用属性名字来引用。
mapper 接口:
List<User> selectByExample(UserExample example);
sql 映射文件:
<where> <foreach collection="oredCriteria" item="criteria" separator="or"> <if test="criteria.valid"> </where>
在这里,UserExample 有一个属性叫 oredCriteria, 其类型为 List, 所以在 foreach 元素里直接用属性名 oredCriteria 引用这个 List 即可。
item="criteria" 表示使用 criteria 这个名字引用每一个集合中的每一个 List 或 Array 元素。
4.2、输出映射
输出映射主要有两种方式指定 ResultType 或 ResultMap，现在分别介绍一下：
4.2.1、ResultType
使用 ResultType进行输出映射，只有查询出来的列名和pojo中的属性名一致，该列才可以映射成功。
如果查询出来的列名和 POJO中的属性名全部不一致，没有创建 POJO对象。
只要查询出来的列名和 POJO中的属性有一个一致，就会创建 POJO对象。
（一）、输出简单类型
接口：
/** * 获得学生总数 * */ long selectStudentsCount();
映射：
<select id="selectStudentsCount" resultType="long"> SELECT count(*) from student </select>
测试：
/** * Method: selectStudentsCount() */ @Test public void testSelectStudentsCount() throws Exception { Assert.assertNotEquals(0,dao.selectStudentsCount());}
结果：
查询出来的结果集只有一行一列，可以使用简单类型进行输出映射。
( 二）、输出 POJO 对象和 POJO 列表
不管是输出的POJO单个对象还是一个列表（List中存放 POJO），在mapper.xml中 ResultType指定的类型是一样的，但方法返回值类型不一样。
输出单个 POJO 对象，方法返回值是单个对象类型
接口：
/** * 根据学生编号获得学生对象 */ Student selectStudentById(int id);
映射：
<select id="selectStudentById" resultType="Student"> SELECT id,name,sex from student where id=#{id} </select>
输出 pojo 对象 list，方法返回值是 List<POJO>
接口：
/** * 根据学生姓名获得学生集合 */ List<Student> selectStudentsByName(String name);
映射：
<select id="selectStudentsByName" parameterType="String" resultType="student"> SELECT id,name,sex from student where name like '%${value}%'; </select>
生成的动态代理对象中是根据 mapper.java 方法的返回值类型确定是调用 selectOne(返回单个对象调用) 还是 selectList(返回集合对象调用)
4.2.2、ResultMap
MyBatis中使用 ResultMap完成自定义输出结果映射，如一对多，多对多关联关系。
问题：
假定 POJO 对象与表中的字段不一致，如下所示:
接口：
/** * 根据性别获得学生集合 */ List<Stu> selectStudentsBySex(String sex);
映射：
<select id="selectStudentsBySex" parameterType="String" resultType="stu"> SELECT id,name,sex from student where sex=#{sex}; </select>
测试：
/** * Method: selectStudentsBySex(String sex) */ @Test public void testSelectStudentsBySex() throws Exception { List<Stu> students=dao.selectStudentsBySex("boy"); System.out.println(students); Assert.assertNotNull(students.get(0));}
结果：
（一）、定义并引用 ResultMap
修改映射文件：
<!--定义结果映射，id 是引用时的编号需唯一，stu 是最终被映射的类型--> <resultMap id="stuMap" type="stu"> <!--映射结果,collumn 表示列名，property 表示属性名--> <result column="id" property="stu_id"></result> <result column="name" property="stu_name"></result> <result column="sex" property="stu_sex"></result> </resultMap><span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">resultMap指定引用的映射</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsBySex"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><span style="color: rgba(255, 0, 0, 1)"> resultMap</span><span style="color: rgba(0, 0, 255, 1)">="stuMap"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where sex=#{sex}; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span></pre>
测试结果：
（二）、使用别名
修改映射文件：
<select id="selectStudentsBySex" parameterType="String" resultType="stu"> SELECT id stu_id,name stu_name,sex as stu_sex from student where sex=#{sex}; </select>
测试结果：
4.2.3、返回 Map
假定要返回 id 作为 key，name 作为 value 的 Map。
接口：
/** * 获得所有学生 Map 集合 */ List<Map<String,Object>> selectAllStudents();
映射：
<resultMap id="stuKeyValueMap" type="HashMap"> <result property="name" column="NAME"></result> <result property="value" column="VALUE"></result> </resultMap><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectAllStudents"</span><span style="color: rgba(255, 0, 0, 1)"> resultMap</span><span style="color: rgba(0, 0, 255, 1)">="stuKeyValueMap"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id NAME,name VALUE from student; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span></pre>
测试：
/** * Method: selectAllStudents() */ @Test public void testSelectAllStudents() throws Exception { List<Map<String,Object>> students=dao.selectAllStudents(); System.out.println(students); Assert.assertNotNull(students); }
结果：
<resultMap id="pieMap" type="HashMap"> <result property="value" column="VALUE" /> <result property="name" column="NAME" /> </resultMap><select id="queryPieParam" parameterType="String" resultMap="pieMap">
SELECT
PLAT_NAME NAME,
<if test='_parameter ==" 总量 "'>
AMOUNT VALUE
</if>
<if test='_parameter ==" 总额 "'>
TOTALS VALUE
</if>
FROM
DOMAIN_PLAT_DEAL_PIE
ORDER BY
<if test='_parameter ==" 总量 "'>
AMOUNT
</if>
<if test='_parameter ==" 总额 "'>
TOTALS
</if>
ASC
</select>
用resultType进行输出映射，只有查询出来的列名和pojo中的属性名一致，该列才可以映射成功。
如果查询出来的列名和pojo的属性名不一致，通过定义一个resultMap对列名和pojo属性名之间作一个映射关系。
最终完成的映射器：
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.zhangguo.mybatis03.dao.StudentMapper"><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentById"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="Student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsCount"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="long"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT count(*) from student </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByName"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where name like '%${value}%'; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">resultMap </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="stuKeyValueMap"</span><span style="color: rgba(255, 0, 0, 1)"> type</span><span style="color: rgba(0, 0, 255, 1)">="HashMap"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">result </span><span style="color: rgba(255, 0, 0, 1)">property</span><span style="color: rgba(0, 0, 255, 1)">="name"</span><span style="color: rgba(255, 0, 0, 1)"> column</span><span style="color: rgba(0, 0, 255, 1)">="NAME"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">result</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">result </span><span style="color: rgba(255, 0, 0, 1)">property</span><span style="color: rgba(0, 0, 255, 1)">="value"</span><span style="color: rgba(255, 0, 0, 1)"> column</span><span style="color: rgba(0, 0, 255, 1)">="VALUE"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">result</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">resultMap</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectAllStudents"</span><span style="color: rgba(255, 0, 0, 1)"> resultMap</span><span style="color: rgba(0, 0, 255, 1)">="stuKeyValueMap"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id NAME,name VALUE from student; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">定义结果映射，id是引用时的编号需唯一，stu是最终被映射的类型</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">resultMap </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="stuMap"</span><span style="color: rgba(255, 0, 0, 1)"> type</span><span style="color: rgba(0, 0, 255, 1)">="stu"</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">映射结果,collumn表示列名，property表示属性名</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">result </span><span style="color: rgba(255, 0, 0, 1)">column</span><span style="color: rgba(0, 0, 255, 1)">="id"</span><span style="color: rgba(255, 0, 0, 1)"> property</span><span style="color: rgba(0, 0, 255, 1)">="stu_id"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">result</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">result </span><span style="color: rgba(255, 0, 0, 1)">column</span><span style="color: rgba(0, 0, 255, 1)">="name"</span><span style="color: rgba(255, 0, 0, 1)"> property</span><span style="color: rgba(0, 0, 255, 1)">="stu_name"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">result</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">result </span><span style="color: rgba(255, 0, 0, 1)">column</span><span style="color: rgba(0, 0, 255, 1)">="sex"</span><span style="color: rgba(255, 0, 0, 1)"> property</span><span style="color: rgba(0, 0, 255, 1)">="stu_sex"</span><span style="color: rgba(0, 0, 255, 1)">></</span><span style="color: rgba(128, 0, 0, 1)">result</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">resultMap</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">resultMap指定引用的映射</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"><select id="selectStudentsBySex" parameterType="String" resultMap="stuMap"></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)">SELECT id,name,sex from student where sex=#{sex};</span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 128, 0, 1)"><!--</span><span style="color: rgba(0, 128, 0, 1)"></select></span><span style="color: rgba(0, 128, 0, 1)">--></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsBySex"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="String"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="stu"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id stu_id,name stu_name,sex as stu_sex from student where sex=#{sex}; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByNameOrSex"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where name like '%${realname}%' or sex=#{sex}; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">select </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="selectStudentsByIdOrSex"</span><span style="color: rgba(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> SELECT id,name,sex from student where id=#{no} or sex=#{sex}; </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">insert </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="insertStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> insert into student(name,sex) VALUES(#{name},'${sex}') </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">insert</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">update </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="updateStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="student"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> update student set name=#{name},sex=#{sex} where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">update</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">delete </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="deleteStudent"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="int"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> delete from student where id=#{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">delete </span><span style="color: rgba(255, 0, 0, 1)">id</span><span style="color: rgba(0, 0, 255, 1)">="deleteStudents"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> delete from student where id in </span><span style="color: rgba(0, 0, 255, 1)"><</span><span style="color: rgba(128, 0, 0, 1)">foreach </span><span style="color: rgba(255, 0, 0, 1)">collection</span><span style="color: rgba(0, 0, 255, 1)">="list"</span><span style="color: rgba(255, 0, 0, 1)"> item</span><span style="color: rgba(0, 0, 255, 1)">="id"</span><span style="color: rgba(255, 0, 0, 1)"> open</span><span style="color: rgba(0, 0, 255, 1)">="("</span><span style="color: rgba(255, 0, 0, 1)"> separator</span><span style="color: rgba(0, 0, 255, 1)">=","</span><span style="color: rgba(255, 0, 0, 1)"> close</span><span style="color: rgba(0, 0, 255, 1)">=")"</span><span style="color: rgba(0, 0, 255, 1)">></span><span style="color: rgba(0, 0, 0, 1)"> #{id} </span><span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">foreach</span><span style="color: rgba(0, 0, 255, 1)">></span> <span style="color: rgba(0, 0, 255, 1)"></</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">></span></mapper>
最终完成的数据访问类似：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Stu;
import com.zhangguo.mybatis03.entities.Student;
import com.zhangguo.mybatis03.utils.SqlSessionFactoryUtil;
import org.apache.ibatis.session.SqlSession;import java.util.List;
import java.util.Map;public class StudentDao implements StudentMapper {
</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生编号获得学生对象 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> Student selectStudentById(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id) { Student entity </span>= <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询单个对象，指定参数为3</span> entity =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentById(id); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> entity; } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获得学生总数 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">long</span><span style="color: rgba(0, 0, 0, 1)"> selectStudentsCount() { </span><span style="color: rgba(0, 0, 255, 1)">long</span> count = 0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询单行单列，简单值</span> count =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentsCount(); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
</span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> count; } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Student><span style="color: rgba(0, 0, 0, 1)"> selectStudentsByName(String name) { List</span><Student> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentsByName(name); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获得所有学生Map集合 * </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Map<String, Object>><span style="color: rgba(0, 0, 0, 1)"> selectAllStudents() { List</span><Map<String, Object>> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectAllStudents(); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据性别获得学生集合 * * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> sex </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Stu><span style="color: rgba(0, 0, 0, 1)"> selectStudentsBySex(String sex) { List</span><Stu> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentsBySex(sex); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名或性别获得学生集合 * * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> name * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> sex </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Student><span style="color: rgba(0, 0, 0, 1)"> selectStudentsByNameOrSex(String name, String sex) { List</span><Student> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentsByNameOrSex(name, sex); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生Id或性别获得学生集合 * * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> param </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> List<Student> selectStudentsByIdOrSex(Map<String, Object><span style="color: rgba(0, 0, 0, 1)"> param) { List</span><Student> entities = <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">查询多个对象，指定参数</span> entities =<span style="color: rgba(0, 0, 0, 1)"> mapper.selectStudentsByIdOrSex(param); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return entities;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 添加学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> insertStudent(Student entity) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows = 0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行添加</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.insertStudent(entity); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 更新学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> updateStudent(Student entity) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows = 0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行更新</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.updateStudent(entity); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudent(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows = 0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行删除</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.deleteStudent(id); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除多个学生通过编号 * * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> ids </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudents(List<Integer><span style="color: rgba(0, 0, 0, 1)"> ids) { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">影响行数</span> <span style="color: rgba(0, 0, 255, 1)">int</span> rows = 0<span style="color: rgba(0, 0, 0, 1)">; </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">打开一个会话</span> SqlSession session = SqlSessionFactoryUtil.openSession(<span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">获得一个映射器</span> StudentMapper mapper = session.getMapper(StudentMapper.<span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">执行删除</span> rows =<span style="color: rgba(0, 0, 0, 1)"> mapper.deleteStudents(ids); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">关闭</span>SqlSessionFactoryUtil.closeSession(session);
return rows;
}}
最终完成的接口：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Stu;
import com.zhangguo.mybatis03.entities.Student;
import org.apache.ibatis.annotations.Param;import java.util.List;
import java.util.Map;public interface StudentMapper {
/**
* 根据学生编号获得学生对象
*/
Student selectStudentById(int id);</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获得学生总数 * </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">long</span><span style="color: rgba(0, 0, 0, 1)"> selectStudentsCount(); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Student><span style="color: rgba(0, 0, 0, 1)"> selectStudentsByName(String name); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获得所有学生Map集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Map<String,Object>><span style="color: rgba(0, 0, 0, 1)"> selectAllStudents(); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据性别获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Stu><span style="color: rgba(0, 0, 0, 1)"> selectStudentsBySex(String sex); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生姓名或性别获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Student> selectStudentsByNameOrSex(@Param("realname") String name,@Param("sex"<span style="color: rgba(0, 0, 0, 1)">) String sex); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 根据学生Id或性别获得学生集合 </span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> List</span><Student> selectStudentsByIdOrSex(Map<String,Object><span style="color: rgba(0, 0, 0, 1)"> param); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 添加学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> insertStudent(Student entity); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 更新学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> updateStudent(Student entity); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除学生 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudent(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id); </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 删除多个学生通过编号 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">int</span> deleteStudents(List<Integer><span style="color: rgba(0, 0, 0, 1)"> ids);}
最终完成的测试：
package com.zhangguo.mybatis03.dao;import com.zhangguo.mybatis03.entities.Stu;
import com.zhangguo.mybatis03.entities.Student;
import org.junit.*;
import org.junit.runners.MethodSorters;import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;/**
StudentDao Tester.
@author <Authors name>
@version 1.0
@since <pre>09/26/2018</pre>
*/
@FixMethodOrder(MethodSorters.JVM)//指定测试方法按定义的顺序执行
public class StudentDaoTest {
StudentMapper dao;
@Before
public void before() throws Exception {
dao=new StudentDao();
}@After
public void after() throws Exception {
}/**
- Method: selectStudentById(int id)
*/
@Test
public void testSelectStudentById() throws Exception {
Student entity=dao.selectStudentById(1);
System.out.println(entity);
Assert.assertNotNull(entity);
}//
/**
- Method: selectStudentsCount()
*/
@Test
public void testSelectStudentsCount() throws Exception {
Assert.assertNotEquals(0,dao.selectStudentsCount());
}
/**- Method: selectStudentsByName(String name)
*/
@Test
public void testSelectStudentsByName() throws Exception {
List<Student> students=dao.selectStudentsByName("C");
System.out.println(students);
Assert.assertNotNull(students);
}/**
- Method: selectAllStudents()
*/
@Test
public void testSelectAllStudents() throws Exception {
List<Map<String,Object>> students=dao.selectAllStudents();
System.out.println(students);
Assert.assertNotNull(students);
}/**
- Method: selectStudentsBySex(String sex)
*/
@Test
public void testSelectStudentsBySex() throws Exception {
List<Stu> students=dao.selectStudentsBySex("boy");
System.out.println(students);
Assert.assertNotNull(students.get(0));
}/**
- Method: selectStudentsByIdOrSex
*/
@Test
public void testSelectStudentsByNameOrSex() throws Exception {
Map<String ,Object> param=new HashMap<String,Object>();
param.put("no",1);
param.put("sex","girl");
List<Student> students=dao.selectStudentsByIdOrSex(param);
System.out.println(students);
Assert.assertNotNull(students);
}/**
Method: insertStudent
*/
@Test
public void testInsertStudent() throws Exception {
Student entity=new Student();
//entity.setName("张明");
entity.setSex("boy");Assert.assertEquals(1,dao.insertStudent(entity));
}/**
Method: updateStudent
*/
@Test
public void testUpdateStudent() throws Exception {
Student entity=dao.selectStudentById(11);
//entity.setName("张丽美");
entity.setSex("girl");Assert.assertEquals(1,dao.updateStudent(entity));
}/**
- Method: deleteStudent
*/
@Test
public void testDeleteStudent() throws Exception {
Assert.assertEquals(1,dao.deleteStudent(12));
}/**
- Method: deleteStudents
*/
@Test
public void testDeleteStudents() throws Exception {
List<Integer> ids=new ArrayList<Integer>();
ids.add(10);
ids.add(11);
Assert.assertEquals(2,dao.deleteStudents(ids));
}
}
五、示例源代码
https://git.coding.net/zhangguo5/MyBatis03.git
https://git.coding.net/zhangguo5/MyBatis02.git
六、视频
https://www.bilibili.com/video/av32447485/
七、作业
1、重现上所有上课示例
2、请使用 Maven 多模块 +Git+MyBatis 完成一个单表的管理功能，需要 UI, 可以 AJAX 也可以 JSTL 作表示层。
3、分页，多条件组合查询，多表连接（选作）
4、内部测试题（4 个小时）
4.1、请实现一个简易图书管理系统（LibSystem），实现图书管理功能，要求如下：(初级)
1、管理数据库中所有图书（Books），包含图书编号（isbn）、书名（title）、作者（author）、价格（price）、出版日期（publishDate）
2、Maven 多模块 +MySQL+Git+MyBatis+JUnit 单元测试
3、表示层可以是 AJAX 或 JSTL
C10 R(10+10) U10 D10
4.2、请实现一个迷你图书管理系统（LibSystem），实现图书管理功能，要求如下：(中级)
1、管理数据库中所有图书分类（Categories），包含图书编号（id）, 名称（name）
2、管理数据库中所有图书（Books），包含图书编号（isbn）、类别（categoryId，外键）书名（title）、作者（author）、价格（price）、出版日期（publishDate）、封面（cover）、详细介绍（details）
3、分页 10
4、多条件组件查询（3 个以上的条件任意组合）(高级) 10
5、多删除 (高级) 10
6、上传封面 (高级) 10
7、富文本编辑器 (高级) 10