mysql连接池DruidDataSource的使用、配置「建议收藏」

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.11</version>
        </dependency>

import javax.sql.DataSource;

@Configuration
public class MysqlConfig {
    @Value("${mysql.username}")
    private String username;
    @Value("${mysql.password}")
    private String password;
    @Value("${mysql.url}")
    private String url;

    @Bean
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        //dataSource.setDriverClassName(driverClassName);//如果不配置druid会根据url自动识别dbType，然后选择相应的driverClassName
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        dataSource.setValidationQuery("SELECT 1");//用来检测连接是否有效
        dataSource.setTestOnBorrow(false);//借用连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
        dataSource.setTestOnReturn(false);//归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
        //连接空闲时检测，如果连接空闲时间大于timeBetweenEvictionRunsMillis指定的毫秒，执行validationQuery指定的SQL来检测连接是否有效
        dataSource.setTestWhileIdle(true);//如果检测失败，则连接将被从池中去除
        dataSource.setTimeBetweenEvictionRunsMillis(60000);//1分钟
        dataSource.setMaxActive(20);
        dataSource.setInitialSize(5);
        return dataSource;
    }

}

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.21</version>
        </dependency>

DruidPooledConnection connection = null;
PreparedStatement statement = null;
try {
    connection = dataSource.getConnection();
    statement = connection.prepareStatement(sql);
    statement.execute(sql);
} catch (SQLException e) {
    log.error("mysql新增数据异常！sql={}", sql, e);
    throw new SQLException("mysql新增数据异常");
} finally {
    if (statement != null) {
        statement.close();
    }
    // 这里一定要close()。底层是 dataSource.recycle(this) 将连接重新放回了连接池，回收利用
    // 不clone()，每次 getConnection() 都会新建Connection
    // dataSource.recycle(this) -> this.putLast(holder, currentTimeMillis) -> this.connections[this.poolingCount] = e;
    // private volatile DruidConnectionHolder[] connections;
    if (connection != null) {
        connection.close();
    }
}