C3P0数据库连接池使用

1、拷贝jar包：c3p0-0.9.1.2.jar     c3p0-0.9.1.2-jdk1.3.jar    c3p0-oracle-thin-extras-0.9.1.2.jar（oracle需要）

2、书写配制文件放在src目录下：c3p0-config.xml（名字只能是这个）

3、类C3P0Util

c3p0-config.xml 内容：

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
	<!-- This is default config! -->
	<default-config>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">30</property>
		<property name="maxPoolSize">100</property>
		<property name="minPoolSize">10</property>
		<property name="maxStatements">200</property>
	</default-config>

	<!-- This is my config for mysql-->
	<named-config name="mysql">
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/test</property>
		<property name="user">root</property>
		<property name="password"></property>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">30</property>
		<property name="maxPoolSize">100</property>
		<property name="minPoolSize">10</property>
		<property name="maxStatements">200</property>
	</named-config>

	<!-- This is my config for oracle -->
	<named-config name="oracle">
		<property name="driverClass">oracle.jdbc.driver.OracleDriver</property>
		<property name="jdbcUrl">jdbc:oracle:thin:@localhost:1521:orcl</property>
		<property name="user">scott</property>
		<property name="password">liang</property>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">30</property>
		<property name="maxPoolSize">100</property>
		<property name="minPoolSize">10</property>
		<property name="maxStatements">200</property>
	</named-config>
</c3p0-config>

C3P0Util:

package com.liang.util;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import com.mchange.v2.c3p0.ComboPooledDataSource;
/**
 * 数据库工具类
 * @author liang
 *
 */
public class C3P0Util {
	static ComboPooledDataSource cpds=null;
	static{
		//这里有个优点，写好配置文件，想换数据库，简单
		//cpds = new ComboPooledDataSource("oracle");//这是oracle数据库
		cpds = new ComboPooledDataSource("mysql");//这是mysql数据库
	}
	/**
	 * 获得数据库连接
	 * @return   Connection
	 */
	public static Connection getConnection(){
		try {
			return cpds.getConnection();
		} catch (SQLException e) {
			e.printStackTrace();
			return null;
		}
	}

	/**
	 * 数据库关闭操作
	 * @param conn
	 * @param st
	 * @param pst
	 * @param rs
	 */
	public static void close(Connection conn,PreparedStatement pst,ResultSet rs){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if(pst!=null){
			try {
				pst.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
	/**
	 * 测试DBUtil类
	 * @param args
	 */
	public static void main(String[] args) {
		Connection conn=getConnection();
		System.out.println(conn.getClass().getName());
		close(conn,null,null);
	}
}