"什么是 MyBatis？ MyBatis 是支持普通 SQL 查询，存储过程和高级映射的优秀持久层框架。 MyBatis 消除了几乎所有的 JDBC 代码和参数的手工设置以及对结果集的检索。MyBatis 可以使用简单的 XML 或注解用于配置和原始映射，将接口和 Java 的 POJO（Plain ...."

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Mybatis实现数据的增删改查（CRUD）

什么是 MyBatis？

MyBatis 是支持普通 SQL 查询，存储过程和高级映射的优秀持久层框架。 MyBatis 消除了几乎所有的 JDBC 代码和参数的手工设置以及对结果集的检索。MyBatis 可以使用简单的 XML 或注解用于配置和原始映射，将接口和 Java 的 POJO（Plain Old Java Objects，普通的 Java 对象）映射成数据库中的记录。

MyBatis 下载：https://github.com/mybatis/mybatis-3/releases

Mybatis 实例

对一个 User 表的 CRUD 操作：

User 表：

-- ----------------------------
-- Table structure for `user`
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `userName` varchar(50) DEFAULT NULL,
  `userAge` int(11) DEFAULT NULL,
  `userAddress` varchar(200) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO <span style="color: rgba(255, 0, 255, 1)">user</span> VALUES ('1', 'summer', '30', 'shanghai');
INSERT INTO <span style="color: rgba(255, 0, 255, 1)">user</span> VALUES ('2', 'test2', '22', 'suzhou');
INSERT INTO <span style="color: rgba(255, 0, 255, 1)">user</span> VALUES ('3', 'test1', '29', 'some place');
INSERT INTO <span style="color: rgba(255, 0, 255, 1)">user</span> VALUES ('4', 'lu', '28', 'some place');
INSERT INTO <span style="color: rgba(255, 0, 255, 1)">user</span> VALUES ('5', 'xiaoxun', '27', 'nanjing');

在 Src 目录下建一个 mybatis 的 xml 配置文件 Configuration.xml

<?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>
    <!-- mybatis 别名定义 -->
    <typeAliases> 
        <typeAlias alias="User" type="com.mybatis.test.User"/> 
    </typeAliases> 
<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">&gt;</span>
    <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">&gt;</span>
    <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">/&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="com.mysql.jdbc.Driver"</span><span style="color: rgba(0, 0, 255, 1)">/&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;</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/mybatis"</span> <span style="color: rgba(0, 0, 255, 1)">/&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">/&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="admin"</span><span style="color: rgba(0, 0, 255, 1)">/&gt;</span>
        <span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">dataSource</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>
    <span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">environment</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>
<span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">environments</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> mybatis的mapper文件，每个xml配置文件对应一个接口 </span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>
<span style="color: rgba(0, 0, 255, 1)">&lt;</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>
    <span style="color: rgba(0, 0, 255, 1)">&lt;</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/mybatis/test/User.xml"</span><span style="color: rgba(0, 0, 255, 1)">/&gt;</span>
<span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">mappers</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

</configuration>

定义 User mappers 的 User.xml 配置文件

<?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.mybatis.test.IUserOperation">
<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> select语句 </span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>
<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="selectUserByID"</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(255, 0, 0, 1)"> resultType</span><span style="color: rgba(0, 0, 255, 1)">="User"</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span><span style="color: rgba(0, 0, 0, 1)">
    select * from `user` where user.id = #{id}
</span><span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> 定义的resultMap，可以解决类的属性名和数据库列名不一致的问题</span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>
<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> &lt;resultMap type="User" id="userResultMap"&gt;
    &lt;id property="id" column="user_id"  /&gt;
    &lt;result property="userName" column="user_userName"  /&gt;
    &lt;result property="userAge" column="user_userAge"  /&gt;
    &lt;result property="userAddress" column="user_userAddress"  /&gt;
&lt;/resultMap&gt; </span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>

<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> 返回list的select语句，注意 resultMap的值是指向前面定义好的 </span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>
<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)"> &lt;select id="selectUsersByName" parameterType="string" resultMap="userResultMap"&gt;
    select * from user where user.userName = #{userName}
&lt;/select&gt; </span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span>

<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="selectUsersByName"</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)">="User"</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span><span style="color: rgba(0, 0, 0, 1)">
    select * from user where user.userName = #{userName}
</span><span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">select</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

<span style="color: rgba(0, 128, 0, 1)">&lt;!--</span><span style="color: rgba(0, 128, 0, 1)">执行增加操作的SQL语句。id和parameterType分别与IUserOperation接口中的addUser方法的名字和参数类型一致。
useGeneratedKeys设置为"true"表明要MyBatis获取由数据库自动生成的主键；keyProperty="id"指定把获取到的主键值注入到User的id属性</span><span style="color: rgba(0, 128, 0, 1)">--&gt;</span> 
<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="addUser"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="User"</span><span style="color: rgba(255, 0, 0, 1)"> 
    useGeneratedKeys</span><span style="color: rgba(0, 0, 255, 1)">="true"</span><span style="color: rgba(255, 0, 0, 1)"> keyProperty</span><span style="color: rgba(0, 0, 255, 1)">="id"</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span><span style="color: rgba(0, 0, 0, 1)"> 
    insert into user(userName,userAge,userAddress)  
         values(#{userName},#{userAge},#{userAddress})  
</span><span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">insert</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="updateUser"</span><span style="color: rgba(255, 0, 0, 1)"> parameterType</span><span style="color: rgba(0, 0, 255, 1)">="User"</span> <span style="color: rgba(0, 0, 255, 1)">&gt;</span><span style="color: rgba(0, 0, 0, 1)">
    update user set userName=#{userName},userAge=#{userAge},userAddress=#{userAddress} where id=#{id}
</span><span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">update</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

<span style="color: rgba(0, 0, 255, 1)">&lt;</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)">="deleteUser"</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)">&gt;</span><span style="color: rgba(0, 0, 0, 1)">
    delete from user where id=#{id}
</span><span style="color: rgba(0, 0, 255, 1)">&lt;/</span><span style="color: rgba(128, 0, 0, 1)">delete</span><span style="color: rgba(0, 0, 255, 1)">&gt;</span>

</mapper>

配置文件实现了接口和 SQL 语句的映射关系。selectUsersByName 采用了 2 种方式实现，注释掉的也是一种实现，采用 resultMap 可以把属性和数据库列名映射关系定义好，property 为类的属性，column 是表的列名，也可以是表列名的别名！

User 类的定义：

package com.mybatis.test;
public class User {
</span><span style="color: rgba(0, 0, 255, 1)">private</span> <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, 0, 255, 1)">private</span><span style="color: rgba(0, 0, 0, 1)"> String userName;
</span><span style="color: rgba(0, 0, 255, 1)">private</span> <span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> userAge;
</span><span style="color: rgba(0, 0, 255, 1)">private</span><span style="color: rgba(0, 0, 0, 1)"> String userAddress;

</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)"> getId() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> id;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span> setId(<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, 0, 255, 1)">this</span>.id =<span style="color: rgba(0, 0, 0, 1)"> id;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String getUserName() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> userName;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> setUserName(String userName) {
    </span><span style="color: rgba(0, 0, 255, 1)">this</span>.userName =<span style="color: rgba(0, 0, 0, 1)"> userName;
}

</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)"> getUserAge() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> userAge;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span> setUserAge(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> userAge) {
    </span><span style="color: rgba(0, 0, 255, 1)">this</span>.userAge =<span style="color: rgba(0, 0, 0, 1)"> userAge;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String getUserAddress() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> userAddress;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> setUserAddress(String userAddress) {
    </span><span style="color: rgba(0, 0, 255, 1)">this</span>.userAddress =<span style="color: rgba(0, 0, 0, 1)"> userAddress;
}

@Override
</span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String toString(){
    </span><span style="color: rgba(0, 0, 255, 1)">return</span> <span style="color: rgba(0, 0, 255, 1)">this</span>.userName+" "+<span style="color: rgba(0, 0, 255, 1)">this</span>.userAge+" "+<span style="color: rgba(0, 0, 255, 1)">this</span><span style="color: rgba(0, 0, 0, 1)">.userAddress;
}

}

IUserOperaton 定义：

package com.mybatis.test;
import java.util.List;
public interface IUserOperation {
</span><span style="color: rgba(0, 0, 255, 1)">public</span> User selectUserByID(<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, 0, 255, 1)">public</span> List&lt;User&gt;<span style="color: rgba(0, 0, 0, 1)"> selectUsersByName(String userName);

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> addUser(User user);

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> updateUser(User user);

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span> deleteUser(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id);

}

IUserOperation 为操作接口，函数名和 mybatis 的 xml 配置文件中的操作 id 名对应。

测试类 Test：

package com.mybatis.test;
import java.io.Reader;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
public class Test {
</span><span style="color: rgba(0, 0, 255, 1)">private</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> SqlSessionFactory sqlSessionFactory;
</span><span style="color: rgba(0, 0, 255, 1)">private</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> Reader reader;

</span><span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> {
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        reader </span>= Resources.getResourceAsReader("Configuration.xml"<span style="color: rgba(0, 0, 0, 1)">);
        sqlSessionFactory </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> SqlSessionFactoryBuilder().build(reader);
    } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (Exception e) {
        e.printStackTrace();
    }
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> SqlSessionFactory getSession() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span> getUserByID(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> userID) {
    SqlSession session </span>=<span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory.openSession();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        IUserOperation userOperation </span>=<span style="color: rgba(0, 0, 0, 1)"> session
                .getMapper(IUserOperation.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">);
        User user </span>=<span style="color: rgba(0, 0, 0, 1)"> userOperation.selectUserByID(userID);
        </span><span style="color: rgba(0, 0, 255, 1)">if</span> (user != <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">) {
            System.out.println(user.getId() </span>+ ":" +<span style="color: rgba(0, 0, 0, 1)"> user.getUserName()
                    </span>+ ":" +<span style="color: rgba(0, 0, 0, 1)"> user.getUserAddress());
        }

    } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> {
        session.close();
    }
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> getUserList(String userName) {
    SqlSession session </span>=<span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory.openSession();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        IUserOperation userOperation </span>=<span style="color: rgba(0, 0, 0, 1)"> session
                .getMapper(IUserOperation.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">);
        List</span>&lt;User&gt; users =<span style="color: rgba(0, 0, 0, 1)"> userOperation.selectUsersByName(userName);
        </span><span style="color: rgba(0, 0, 255, 1)">for</span><span style="color: rgba(0, 0, 0, 1)"> (User user : users) {
            System.out.println(user.getId() </span>+ ":" +<span style="color: rgba(0, 0, 0, 1)"> user.getUserName()
                    </span>+ ":" +<span style="color: rgba(0, 0, 0, 1)"> user.getUserAddress());
        }

    } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> {
        session.close();
    }
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 增加后要commit
 </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)">void</span><span style="color: rgba(0, 0, 0, 1)"> addUser() {
    User user </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> User();
    user.setUserAddress(</span>"place"<span style="color: rgba(0, 0, 0, 1)">);
    user.setUserName(</span>"test_add"<span style="color: rgba(0, 0, 0, 1)">);
    user.setUserAge(</span>30<span style="color: rgba(0, 0, 0, 1)">);
    SqlSession session </span>=<span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory.openSession();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        IUserOperation userOperation </span>=<span style="color: rgba(0, 0, 0, 1)"> session
                .getMapper(IUserOperation.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">);
        userOperation.addUser(user);
        session.commit();
        System.out.println(</span>"新增用户ID：" +<span style="color: rgba(0, 0, 0, 1)"> user.getId());
    } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> {
        session.close();
    }
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 修改后要commit
 </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)">void</span><span style="color: rgba(0, 0, 0, 1)"> updateUser() {
    SqlSession session </span>=<span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory.openSession();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        IUserOperation userOperation </span>=<span style="color: rgba(0, 0, 0, 1)"> session
                .getMapper(IUserOperation.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">);
        User user </span>= userOperation.selectUserByID(1<span style="color: rgba(0, 0, 0, 1)">);
        </span><span style="color: rgba(0, 0, 255, 1)">if</span> (user != <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">) {
            user.setUserAddress(</span>"A new place"<span style="color: rgba(0, 0, 0, 1)">);
            userOperation.updateUser(user);
            session.commit();
        }
    } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> {
        session.close();
    }
}

</span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)">
 * 删除后要commit.
 * 
 * </span><span style="color: rgba(128, 128, 128, 1)">@param</span><span style="color: rgba(0, 128, 0, 1)"> id
 </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)">void</span> deleteUser(<span style="color: rgba(0, 0, 255, 1)">int</span><span style="color: rgba(0, 0, 0, 1)"> id) {
    SqlSession session </span>=<span style="color: rgba(0, 0, 0, 1)"> sqlSessionFactory.openSession();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        IUserOperation userOperation </span>=<span style="color: rgba(0, 0, 0, 1)"> session
                .getMapper(IUserOperation.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">);
        userOperation.deleteUser(id);
        session.commit();
    } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> {
        session.close();
    }
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> main(String[] args) {
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        Test test </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> Test();
        </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> test.getUserByID(1);
        </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> test.getUserList("test1");
        </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> test.addUser();
        </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> test.updateUser();
        </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)"> test.deleteUser(6);</span>


        } catch (Exception e) {System.out.println(e.getMessage());
        }
    }
}

MyBatis Mapper 单个参数、多个参数传参区别

1、单个参数

mybatis 不会做特殊处理
#{参数名 / 任意名}：取出参数值。

在接口EmployeeMapper.java中有

public Employee getEmpById(Integer id);

EmployeeMapper.xml中用#{id}取出参数值，因为只有一个，用任意名也可以，如下：

<select id="getEmpById" resultType="com.atguigu.mybatis.bean.Employee">
         select * from tbl_employee where id = #{abcde}
</select>

2、多个参数

mybatis 会做特殊处理

我们在接口EmployeeMapper.java中新加一个方法：

public Employee getEmpByIdAndLastName(Integer id,String lastName);

取值方法：用#{id},#{lastName}这种方式取出参数

<select id="getEmpByIdAndLastName" resultType="com.atguigu.mybatis.bean.Employee">
        select * from tbl_employee where id = #{id} and last_name=#{lastName}
    </select>

结果出异常了：

    org.apache.ibatis.binding.BindingException: 
    Parameter 'id' not found. 
    Available parameters are [1, 0, param1, param2]

【命名参数】：明确指定封装参数：

public Employee getEmpByIdAndLastName(@Param("id") Integer id, @Param("lastName") String lastName);

这样就用#{id},#{lastName}这种方式取出参数了：

<select id="getEmpByIdAndLastName" resultType="com.atguigu.mybatis.bean.Employee">
        select * from tbl_employee where id = #{id} and last_name=#{lastName}
</select>

代码下载：http://download.csdn.net/detail/luxiaoxun/8056559

参考：

http://www.mybatis.org/mybatis-3/zh/getting-started.html

http://legend2011.blog.51cto.com/3018495/d-5

http://mybatis.github.io/mybatis-3/zh/sqlmap-xml.html

Mybatis实现数据的增删改查（CRUD）

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