Java 数据库连接池介绍(5)--Druid 介绍
Druid 连接池是阿里巴巴开源的数据库连接池项目，Druid 为监控而生，内置强大的监控功能，监控特性不影响性能，官网地址为：https://github.com/alibaba/druid/wiki/Druid%E8%BF%9E%E6%8E%A5%E6%B1%A0%E4%BB%8B%E7%BB%8D；本文主要介绍 Druid 的基本使用，文中使用到的软件版本：Java 1.8.0_191、Druid 1.2.8、Spring Boot 2.3.12.RELEASE。
1、配置参数
Druid 连接池的配置参数兼容 DBCP，个别配置的语意有所区别。
2、使用
2.1、直接使用
2.1.1、引入依赖
<dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.2.8</version> </dependency>
2.1.2、使用例子
package com.abc.demo.general.dbpool;import com.alibaba.druid.pool.DruidDataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class DruidCase {
public static void main(String[] args) {
DruidDataSource druidDataSource = new DruidDataSource();
Connection connection = null;
try {
druidDataSource.setName("测试连接池");
druidDataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
druidDataSource.setUrl("jdbc:mysql://10.49.196.11:3306/mydb?useUnicode=true&characterEncoding=UTF-8");
druidDataSource.setUsername("root");
druidDataSource.setPassword("123456");
druidDataSource.setInitialSize(2);
druidDataSource.setMinIdle(2);
druidDataSource.setMaxActive(5);
druidDataSource.setValidationQuery("select 1");
druidDataSource.setTestWhileIdle(true);
druidDataSource.setTestOnBorrow(true);
druidDataSource.setTestOnReturn(false);
druidDataSource.setMaxWait(6000);
druidDataSource.setFilters("slf4j");connection </span>=<span style="color: rgba(0, 0, 0, 1)"> druidDataSource.getConnection(); Statement st </span>=<span style="color: rgba(0, 0, 0, 1)"> connection.createStatement(); ResultSet rs </span>= st.executeQuery("select version()"<span style="color: rgba(0, 0, 0, 1)">); </span><span style="color: rgba(0, 0, 255, 1)">if</span><span style="color: rgba(0, 0, 0, 1)"> (rs.next()) { System.out.println(rs.getString(</span>1<span style="color: rgba(0, 0, 0, 1)">)); } } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) { e.printStackTrace(); } </span><span style="color: rgba(0, 0, 255, 1)">finally</span><span style="color: rgba(0, 0, 0, 1)"> { close(connection); } </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">实际使用中一般是在应用启动时初始化数据源，应用从数据源中获取连接；并不会关闭数据源。</span>druidDataSource.close();
}</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, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> close(Connection connection) { </span><span style="color: rgba(0, 0, 255, 1)">if</span> (connection != <span style="color: rgba(0, 0, 255, 1)">null</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)"> { connection.close(); } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) { e.printStackTrace(); } } }}
2.2、在 SpringBoot 中使用
2.1.1、引入依赖
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.12.RELEASE</version> <relativePath /> </parent><dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency><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.springframework<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>spring-jdbc<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)">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)">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>com.alibaba<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>druid-spring-boot-starter<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>1.2.8<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, 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)">dependency</span><span style="color: rgba(0, 0, 255, 1)">></span></dependencies>
2.1.2、单数据源
application.yml 配置：
spring: datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://10.49.196.11:3306/mydb?useUnicode=true&characterEncoding=UTF-8 username: root password: 123456 type: com.alibaba.druid.pool.DruidDataSource druid: initial-size: 2 min-idle: 2 max-active: 5 validation-query: select 1 test-while-idle: true test-on-borrow: true test-on-return: false max-wait: 6000 filter: slf4j
使用：
@Autowired private DataSource dataSource;
2.1.3、多数据源
application.yml 配置：
spring: datasource: druid: db1: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://10.140.9.11:3306/mydb?useUnicode=true&characterEncoding=UTF-8 username: root password: 123456 initial-size: 2 min-idle: 2 max-active: 5 validation-query: select 1 test-while-idle: true test-on-borrow: true test-on-return: false max-wait: 6000 filter: slf4j db2: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://10.49.196.12:3306/mydb?useUnicode=true&characterEncoding=UTF-8 username: root password: 123456 initial-size: 2 min-idle: 2 max-active: 5 validation-query: select 1 test-while-idle: true test-on-borrow: true test-on-return: false max-wait: 6000 filter: slf4j
数据源配置类：
package com.abc.demo.config;import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;import javax.sql.DataSource;
@Configuration
public class DataSourceConfig {
@Primary
@Bean("dataSource1")
@ConfigurationProperties("spring.datasource.druid.db1")
public DataSource dataSourceOne(){
return DruidDataSourceBuilder.create().build();
}@Bean(</span>"dataSource2"<span style="color: rgba(0, 0, 0, 1)">) @ConfigurationProperties(</span>"spring.datasource.druid.db2"<span style="color: rgba(0, 0, 0, 1)">) </span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> DataSource dataSourceTwo(){ </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> DruidDataSourceBuilder.create().build(); }}
使用：
@Autowired @Qualifier("dataSource1") private DataSource dataSource1;@Autowired
@Qualifier("dataSource2")
private DataSource dataSource2;
2.1.4、开启监控功能
Druid 内置了一些监控，Spring Boot 环境下通过少量配置就可开启这些功能。
application.yml 配置：
spring: datasource: driver-class-name: com.mysql.cj.jdbc.Driver url: jdbc:mysql://10.49.196.11:3306/mydb?useUnicode=true&characterEncoding=UTF-8 username: root password: InsYR0ot187! type: com.alibaba.druid.pool.DruidDataSource druid: initial-size: 2 min-idle: 2 max-active: 5 validation-query: select 1 test-while-idle: true test-on-borrow: true test-on-return: false max-wait: 6000 filter: slf4j,stat,wall #启用日志、监控统计、防火墙功能 web-stat-filter: #web 监控配置 enabled: true stat-view-servlet: #监控页面配置 enabled: true url-pattern: /druid/*
监控页面：
Spring Boot 中集成 Druid 的详细说明可以参考官网文档：https://hub.fastgit.org/alibaba/druid/tree/master/druid-spring-boot-starter