工具类：获得C3P0连接池的dataSource

//DataSourceUtils.java 通过该工具类可以获得dataSource或connection

package com.songlee.utils;
/*
 * 复杂版C3P0工具类
 */
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


import javax.sql.DataSource;


import com.mchange.v2.c3p0.ComboPooledDataSource;


public class DataSourceUtils {


private static DataSource dataSource = new ComboPooledDataSource();


private static ThreadLocal tl = new ThreadLocal();


// 直接可以获取一个连接池
public static DataSource getDataSource() {
return dataSource;
}


// 获取连接对象
public static Connection getConnection() throws SQLException {


Connection con = tl.get();
if (con == null) {
con = dataSource.getConnection();
tl.set(con);
}
return con;
}


// 开启事务
public static void startTransaction() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.setAutoCommit(false);
}
}


// 事务回滚
public static void rollback() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.rollback();
}
}


// 提交并且 关闭资源及从ThreadLocall中释放
public static void commitAndRelease() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.commit(); // 事务提交
con.close();// 关闭资源
tl.remove();// 从线程绑定中移除
}
}


// 关闭资源方法
public static void closeConnection() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.close();
}
}


public static void closeStatement(Statement st) throws SQLException {
if (st != null) {
st.close();
}
}


public static void closeResultSet(ResultSet rs) throws SQLException {
if (rs != null) {
rs.close();
}
}


}