javaweb-c3p0连接池

最常用的连接池技术，Spring默认支持c3p0连接池。

核心类

1. CombopooledDataSource ds;

引入，c3p0的jar包

2.使用链接池，创建链接

a)硬编码方式

    public void testCode() throws Exception{

        //创建连接池工具类
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        //设置连接参数
        dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/learnstruts");
        dataSource.setDriverClass("com.mysql.jdbc.Driver");
        dataSource.setUser("root");
        dataSource.setPassword("33269456.cx");

        dataSource.setInitialPoolSize(3);
        dataSource.setMaxPoolSize(6);

        //取得链接对象
        java.sql.Connection connection = dataSource.getConnection();

        connection.prepareStatement("DELETE FROM user WHERE userId = ‘1‘").executeUpdate();

        //关闭
        connection.close();

    }

b)xml配置方式

c3p0-config.xml

<c3p0-config>
  <default-config>

     <property name="driverClass">com.mysql.jdbc.Driver</property>
     <property name="jdbcUrl">jdbc:mysql://localhost:3306/learnstruts</property>
     <property name="user">root</property>
     <property name="password">33269456.cx</property>
     <property name="initialPoolSize">5</property>
     <property name="maxPoolSize">10</property> 

  </default-config>

<!--
  <named-config name="oracleConfig">
    <property name="driverClass">com.mysql.jdbc.Driver</property>
     <property name="jdbcUrl">jdbc:mysql:///day17</property>
     <property name="user">root</property>
     <property name="password">root</property>
     <property name="initialPoolSize">5</property>
     <property name="maxPoolSize">10</property>
   </named-config>
-->
</c3p0-config>

 @Test
    public void testXML() throws Exception{

        //在这个类会自动加载src下的c3p0配置文件
        ComboPooledDataSource dataSource = new ComboPooledDataSource();

        Connection connection = dataSource.getConnection();

        connection.prepareStatement("DELETE FROM user WHERE userId = ‘1‘");

        connection.close();
    }

JdbcUtil.javpackage com.cx.utils;

import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class JdbcUtils {

    //初始化连接池
    private static DataSource dataSource;

   //静态代码块加载连接池，只加载一次
    static {
        //从连接池中拿到数据源
        dataSource = new ComboPooledDataSource();
    }

    //封装常用对象
    public static DataSource getDataSource() {
        return dataSource;
    }

    public static QueryRunner getQueryRunner() {
        return new QueryRunner(dataSource);
    }
}