DataSourceUtils.txt

package ****；

import java.sql.Connection;
import java.sql.SQLException;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class MyDataSource {
	//获得connection---------从连接池中获取
	private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
	//创建ThreadLocal
	private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>();
	
	/*
	 * 开启事务
	 */
	public static void startTransation() throws SQLException {
		Connection conn = getCurrentConnection();
		conn.setAutoCommit(false);
	}
	
	/*
	 * 回滚事务
	 */
	public static void rollBack() throws SQLException {
		getCurrentConnection().rollback();
	}
	
	/*
	 * 提交事务
	 */
	public static void commit() throws SQLException {
		Connection conn = getCurrentConnection();
		conn.commit();
		//提交后将本次connection从ThreadLocal中移除
		tl.remove();
		conn.close();
	}
	
	/*
	 * 一般方法的增强，利用线程,获得当前线程上绑定的connection
	 */
	public static Connection getCurrentConnection() throws SQLException {
		//先从ThreadLocal中寻找当前线程是否有对应的Connection
		Connection conn = tl.get();
		//判断conn是否为空
		if(conn == null) {
			//获得新的connection
			conn = getConnection();
			//新获得的connection存入ThreadLocal中
			tl.set(conn);
		}
		return conn;
	}
	
	/*
	 * 一般方法
	 */
	public static Connection getConnection() throws SQLException {
		return dataSource.getConnection();
	}

}