java-事务-案例

项目结构：

数据库：

/*
SQLyog Ultimate v12.09 (64 bit)
MySQL - 5.5.53 : Database - threadlocal
*********************************************************************
*/

/*!40101 SET NAMES utf8 */;

/*!40101 SET SQL_MODE=''*/;

/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
CREATE DATABASE /*!32312 IF NOT EXISTS*/`threadlocal` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `threadlocal`;

/*Table structure for table `person` */

DROP TABLE IF EXISTS `person`;

CREATE TABLE `person` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8;

/*Data for the table `person` */

insert  into `person`(`id`,`name`) values (12,'ccc'),(13,'ddd'),(15,'ccc'),(16,'ddd');

/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;

项目代码：

com.gordon.dao:

--SaveDao.java

package com.gordon.dao;

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

import com.gordon.domain.Person;
import com.gordon.utils.DataSourceUtil4threadLocal;

public class SaveDao {

	public void add1(Person p) throws SQLException {
		String sql = "insert into person (name) values (?)";
		Connection connection = DataSourceUtil4threadLocal.getConnection();
		PreparedStatement pst = connection.prepareStatement(sql);
		pst.setString(1, p.getName());
		pst.executeUpdate();
	}

	public void add2(Person p) throws SQLException {
		String sql = "insert into person (name) values (?)";
		Connection connection = DataSourceUtil4threadLocal.getConnection();
		PreparedStatement pst = connection.prepareStatement(sql);
		pst.setString(1, p.getName());
		pst.executeUpdate();
	}

}

com.gordon.domain

--Person.java

package com.gordon.domain;

public class Person {
	private int id;
	private String name;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

com.gordon.service

--SaveService.java

package com.gordon.service;

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

import com.gordon.dao.SaveDao;
import com.gordon.domain.Person;
import com.gordon.utils.DataSourceUtil4threadLocal;

public class SaveService {

	public void thread_add(Person p1, Person p2) throws SQLException {

		Connection connection = DataSourceUtil4threadLocal.getConnection();
		DataSourceUtil4threadLocal.startTransaction();

		SaveDao saveDao = new SaveDao();

		try {
			saveDao.add1(p1);

			//int i = 1 / 0;

			saveDao.add2(p2);

			DataSourceUtil4threadLocal.commitTransaction();
		} catch (Exception e) {
			DataSourceUtil4threadLocal.rollbackTransaction();
			e.printStackTrace();
		}

		DataSourceUtil4threadLocal.closeConn(connection);
	}

	public void add(Person p1, Person p2) {

		SaveDao saveDao = new SaveDao();

		try {
			saveDao.add1(p1);

			// int i = 1 / 0;

			saveDao.add2(p2);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

com.gordon.utils

--DataSourceUtil.java

package com.gordon.utils;

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 DataSourceUtil {
	private static ComboPooledDataSource ds = new ComboPooledDataSource();

	/**
	 * 获取数据源
	 *
	 * @return 连接池
	 */
	public static DataSource getDataSource() {
		return ds;
	}

	/**
	 * 获取连接
	 *
	 * @return 连接
	 * @throws SQLException
	 */
	public static Connection getConnection() throws SQLException {
		return ds.getConnection();
	}

	/**
	 * 释放资源
	 *
	 * @param conn
	 *            连接
	 * @param st
	 *            语句执行者
	 * @param rs
	 *            结果集
	 */
	public static void closeResource(Connection conn, Statement st, ResultSet rs) {
		closeResultSet(rs);
		closeStatement(st);
		closeConn(conn);
	}

	/**
	 * 释放连接
	 *
	 * @param conn
	 *            连接
	 */
	public static void closeConn(Connection conn) {
		if (conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}

	}

	/**
	 * 释放语句执行者
	 *
	 * @param st
	 *            语句执行者
	 */
	public static void closeStatement(Statement st) {
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			st = null;
		}

	}

	/**
	 * 释放结果集
	 *
	 * @param rs
	 *            结果集
	 */
	public static void closeResultSet(ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}

	}
}

--DataSourceUtil4ThreadLocal.java

package com.gordon.utils;

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 DataSourceUtil4threadLocal {
	private static ComboPooledDataSource ds = new ComboPooledDataSource();

	private static ThreadLocal<Connection> threadLocal = new ThreadLocal<>();

	/**
	 * 获取数据源
	 *
	 * @return 连接池
	 */
	public static DataSource getDataSource() {
		return ds;
	}

	/**
	 * 获取连接
	 *
	 * @return 连接
	 * @throws SQLException
	 */
	public static Connection getConnection() throws SQLException {

		Connection connection = threadLocal.get();

		if (connection == null) {
			connection = ds.getConnection();
			threadLocal.set(connection);
		}

		return connection;
	}

	public static void startTransaction() throws SQLException {
		Connection connection = getConnection();
		if (connection != null) {
			connection.setAutoCommit(false);
		}
	}

	public static void commitTransaction() throws SQLException {
		Connection connection = getConnection();
		if (connection != null) {
			connection.commit();
		}
	}

	public static void rollbackTransaction() throws SQLException {
		Connection connection = getConnection();
		if (connection != null) {
			connection.rollback();
		}
	}

	public static void closeConn(Connection conn) {
		if (conn != null) {
			try {
				conn.close();
				threadLocal.remove();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}
	}

	/**
	 * 释放资源
	 *
	 * @param conn
	 *            连接
	 * @param st
	 *            语句执行者
	 * @param rs
	 *            结果集
	 */
	public static void closeResource(Connection conn, Statement st, ResultSet rs) {
		closeResultSet(rs);
		closeStatement(st);
		closeConn(conn);
	}

	/**
	 * 释放语句执行者
	 *
	 * @param st
	 *            语句执行者
	 */
	public static void closeStatement(Statement st) {
		if (st != null) {
			try {
				st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			st = null;
		}

	}

	/**
	 * 释放结果集
	 *
	 * @param rs
	 *            结果集
	 */
	public static void closeResultSet(ResultSet rs) {
		if (rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}

	}
}

com.gordon.web.servlet

--SaveServlet.java

package com.gordon.web.servlet;

import java.io.IOException;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.gordon.domain.Person;
import com.gordon.service.SaveService;

/**
 * Servlet implementation class SaveServlet
 */
@WebServlet("/saveServlet")
public class SaveServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		Person p1 = new Person();
		p1.setName("ccc");

		Person p2 = new Person();
		p2.setName("ddd");

		// new SaveService().add(p1, p2); // 原始方法

		try {
			new SaveService().thread_add(p1, p2); // 通过线程绑定连接
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} 

	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
	 *      response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

c3p0-config.xml

<c3p0-config>
	<!-- 默认配置，如果没有指定则使用这个配置 -->
	<default-config>
		<!-- 基本配置 -->
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/threadlocal</property>
		<property name="user">root</property>
		<property name="password">root</property>

		<!--扩展配置-->
		<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> 

	<!-- 命名的配置 -->
	<named-config name="itcast">
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/xxxx</property>
		<property name="user">root</property>
		<property name="password">1234</property>

		<!-- 如果池中数据连接不够时一次增长多少个 -->
		<property name="acquireIncrement">5</property>
		<property name="initialPoolSize">20</property>
		<property name="minPoolSize">10</property>
		<property name="maxPoolSize">40</property>
		<property name="maxStatements">20</property>
		<property name="maxStatementsPerConnection">5</property>
	</named-config>
</c3p0-config>