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 = druidDataSource.getConnection(); Statement st = connection.createStatement(); ResultSet rs = st.executeQuery("select version()"); if (rs.next()) { System.out.println(rs.getString(1)); } } catch (SQLException e) { e.printStackTrace(); } finally { close(connection); } //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。 druidDataSource.close(); } private static void close(Connection connection) { if (connection != null) { try { connection.close(); } catch (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> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.2.8</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> </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("dataSource2") @ConfigurationProperties("spring.datasource.druid.db2") public DataSource dataSourceTwo(){ return 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
