C3P0配置与使用

一、C3P0配置

1、使用xml方式（名称为c3p0-config.xml）

<?xml version="1.0" encoding="UTF-8"?> <c3p0-config> <default-config> <property name="jdbcUrl">jdbc:mysql://localhost:3306/tv_guide </property> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="user">root</property> <property name="password">root</property> <property name="checkoutTimeout">30000</property> <property name="idleConnectionTestPeriod">30</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> </default-config> </c3p0-config>

2、使用properties方式（名称为c3p0.properties）

c3p0.jdbcUrl=jdbc:mysql://localhost:3306/tv_guide c3p0.driverClass=com.mysql.jdbc.Driver c3p0.user=root c3p0.password=root c3p0.acquireIncrement=3 c3p0.idleConnectionTestPeriod=60 c3p0.initialPoolSize=10 c3p0.maxIdleTime=60 c3p0.maxPoolSize=20 c3p0.maxStatements=100 c3p0.minPoolSize=5

使用这两种方式进行配置时，只要将配置好的文件放入classpath文件夹下即可，在java代码当中不用显示的给出访问配置方式的代码，c3p0会自动识别！

二、C3P0的使用

import java.sql.Connection; import java.sql.SQLException; import javax.sql.DataSource; import com.mchange.v2.c3p0.ComboPooledDataSource; public class C3P0Utils { private static DataSource ds; private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>(); // map static { ds = new ComboPooledDataSource();//直接使用即可，不用显示的配置，其会自动识别配置文件 } public static DataSource getDataSource() { return ds; } public static Connection getConnection() throws SQLException { try { // 得到当前线程上绑定的连接 Connection conn = tl.get(); if (conn == null) { // 代表线程上没有绑定连接 conn = ds.getConnection(); tl.set(conn); } return conn; } catch (Exception e) { throw new RuntimeException(e); } } public static void startTransaction() { try { // 得到当前线程上绑定连接开启事务 Connection conn = tl.get(); if (conn == null) { // 代表线程上没有绑定连接 conn = ds.getConnection(); tl.set(conn); } conn.setAutoCommit(false); } catch (Exception e) { throw new RuntimeException(e); } } public static void commitTransaction() { try { Connection conn = tl.get(); if (conn != null) { conn.commit(); } } catch (Exception e) { throw new RuntimeException(e); } } public static void closeConnection() { try { Connection conn = tl.get(); if (conn != null) { conn.close(); } } catch (Exception e) { throw new RuntimeException(e); } finally { tl.remove(); // 千万注意，解除当前线程上绑定的链接（从threadlocal容器中移除对应当前线程的链接） } } }
详细信息见：http://www.mchange.com/projects/c3p0/c3p0官方网站