利用ThreadLocal管理事務

package com.itheima.util;

import java.sql.Connection;
import java.sql.SQLException;
//封裝了全部與事務有關的方法
public class TransactionManager {
    private static ThreadLocal<Connection> tl = new ThreadLocal<Connection>();
    public static Connection getConnection(){
        Connection conn = tl.get();
        if(conn==null){//從當前線程中獲取連接
            conn = DBCPUtil.getConnection();
            tl.set(conn);
        }
        return conn;
    }
    public static void startTransaction(){
        try {
            Connection conn = getConnection();
            conn.setAutoCommit(false);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    public static void rollback(){
        try {
            Connection conn = getConnection();
            conn.rollback();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    public static void commit(){
        try {
            Connection conn = getConnection();
            conn.commit();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    public static void release(){
        try {
            Connection conn = getConnection();
            conn.close();
            tl.remove();//從當前線程中解綁。  與服務器實現有關：服務器採用線程池。
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}