学步园

本文介绍Spring 的声明式事务配置，使用HibernateTransaction 

applicationContext.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="

http://www.springframework.org/schema/beans


http://www.springframework.org/schema/beans/spring-beans-3.0.xsd


http://www.springframework.org/schema/aop


http://www.springframework.org/schema/aop/spring-aop-3.0.xsd


http://www.springframework.org/schema/tx

		http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

	<bean id="sessionFactory"
		class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
		<property name="configLocations">
			<value>classpath:hibernate.cfg.xml</value>
		</property>
	</bean>

	<bean id="userDao" class="com.dao.impl.UserDaoImpl">
		<property name="sessionFactory" ref="sessionFactory"></property>
	</bean>
	<bean id="logDao" class="com.dao.impl.LogDaoImpl">
		<property name="sessionFactory" ref="sessionFactory"></property>
	</bean>

	<bean id="userService" class="com.service.UserService">
		<property name="userDao" ref="userDao"></property>
		<property name="logDao" ref="logDao"></property>
	</bean>

	<bean id="txManager"
		class="org.springframework.orm.hibernate3.HibernateTransactionManager">
		<property name="sessionFactory" ref="sessionFactory" />
	</bean>

	<aop:config>
		<!-- global pointcut -->
		<aop:pointcut expression="execution(* com.service.*.save(..))"
			id="service" />
		<aop:advisor pointcut-ref="service"
			advice-ref="txAdvice" />
	</aop:config>

	<tx:advice id="txAdvice"  transaction-manager="txManager">
		<tx:attributes>
		<!-- service层里面的方法，不是dao层里面的方法 -->
			<tx:method name="save*" propagation="REQUIRED"/>
		</tx:attributes>
	</tx:advice>
	
</beans>

hibernate.cfg.xml配置文件

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- Database connection settings -->
        <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/spring</property>
        <property name="connection.username">root</property>
        <property name="connection.password">zizhu</property>

        <!-- JDBC connection pool (use the built-in) -->
        <property name="connection.pool_size">10</property>

        <!-- SQL dialect -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Enable Hibernate's automatic session context management -->
        <!-- 此处千万不能打开，否则会报错，第一次就卡在这个地方，这个地方可以直接让spring自己默认配置 -->
<!--        <property name="current_session_context_class">thread</property>-->

        <!-- Disable the second-level cache  -->
        <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

        <!-- Echo all executed SQL to stdout -->
<!--        <property name="show_sql">true</property>-->
        <property name="format_sql">true</property>

        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">update</property>

<!--        <mapping resource="com/model/User.hbm.xml"/>-->
        <mapping class="com.model.User"/>
        <mapping class="com.model.Log"/>

    </session-factory>

</hibernate-configuration>

service层的核心类：

package com.service;

import com.dao.LogDao;
import com.dao.UserDao;
import com.model.Log;
import com.model.User;

public class UserService {
	private UserDao userDao=null;
	private LogDao logDao=null;
	
	public LogDao getLogDao() {
		return logDao;
	}

	public void setLogDao(LogDao logDao) {
		this.logDao = logDao;
	}
	
	/**
	 * 事务的边界只能在service层，当在保存用户或者日志时，任何一个地方出错，
	 * 这个事务都将回滚，这就是为什么事务的边界需要配置在service层的原因
	 * @param user
	 */
	public void save(User user){
		userDao.save(user);
		Log log = new Log();
		log.setContent("a user saved");
		logDao.save(log);
	}

	public UserDao getUserDao() {
		return userDao;
	}

	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}
	
}

在UserDao的具体实现类中不需要session.beginTransaction()，也不需要session.getTransaction().commit()；因为由spring管理事务了

package com.dao.impl;

import org.hibernate.SessionFactory;
import org.hibernate.classic.Session;

import com.dao.UserDao;
import com.model.User;

public class UserDaoImpl implements UserDao{
	private SessionFactory sessionFactory = null;
	
	public SessionFactory getSessionFactory() {
		return sessionFactory;
	}

	public void setSessionFactory(SessionFactory sessionFactory) {
		this.sessionFactory = sessionFactory;
	}

	public void save(User user) {
		Session session = sessionFactory.getCurrentSession();
		/**
		 * 此处直接保存，不需要beginTransaction()
		 */
		session.save(user);
		/**
		 * 最后也不需要commit()
		 * 由spring管理事务
		 */
		System.out.println("Save user:"+user.getUsername());
	}
}

Spring 声明式Transaction，在项目中用的相当多，因此留个备份，方便以后copy改……