深入浅出学习Spring框架（四）：IoC和AOP的应用——事务配置

在前文

深入浅出学习Spring框架（一）：通过Demo阐述IoC和DI的优势所在、

深入浅出学习Spring框架（三）：AOP 详解

分别介绍了Spring的核心功能——IoC和AOP，光讲知识远远不够，重要的得实践才行，今天来谈谈在IoC和AOP基础上配置事务。

Spring配置文件中关于事务配置总是由三个组成部分，分别是DataSource、TransactionManager和代理机制这三部分，无论哪种配置方式，一般变化的只是代理机制这部分。

DataSource、TransactionManager这两部分只是会根据数据访问方式有所变化，比如使用Hibernate进行数据访问时，DataSource实际为SessionFactory，TransactionManager的实现为HibernateTransactionManager。

具体如下图：

根据代理机制的不同，总结了五种Spring事务的配置方式，配置文件如下：

第一种方式：每个Bean都有一个代理

<?xmlversion="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-2.5.xsd
          http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-2.5.xsd">

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

    <!-- 定义事务管理器（声明式的事务） -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <!-- 配置DAO -->
    <bean id="userDaoTarget" class="com.bluesky.spring.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <bean id="userDao"
        class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
           <!-- 配置事务管理器 -->
           <property name="transactionManager" ref="transactionManager" />
        <property name="target" ref="userDaoTarget" />
         <property name="proxyInterfaces" value="com.bluesky.spring.dao.GeneratorDao" />
        <!-- 配置事务属性 -->
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>
</beans>

第二种方式：所有Bean共享一个代理基类

<?xmlversion="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-2.5.xsd
          http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-2.5.xsd">

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

    <!-- 定义事务管理器（声明式的事务） -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <bean id="transactionBase"
           class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"
           lazy-init="true" abstract="true">
        <!-- 配置事务管理器 -->
        <property name="transactionManager" ref="transactionManager" />
        <!-- 配置事务属性 -->
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>    

    <!-- 配置DAO -->
    <bean id="userDaoTarget" class="com.bluesky.spring.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <bean id="userDao" parent="transactionBase" >
        <property name="target" ref="userDaoTarget" />
    </bean>
</beans>

第三种方式：使用拦截器

<?xmlversion="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
          http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-2.5.xsd
          http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-2.5.xsd">

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

    <!-- 定义事务管理器（声明式的事务） -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean> 

    <bean id="transactionInterceptor"
        class="org.springframework.transaction.interceptor.TransactionInterceptor">
        <property name="transactionManager" ref="transactionManager" />
        <!-- 配置事务属性 -->
        <property name="transactionAttributes">
            <props>
                <prop key="*">PROPAGATION_REQUIRED</prop>
            </props>
        </property>
    </bean>

    <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
        <property name="beanNames">
            <list>
                <value>*Dao</value>
            </list>
        </property>
        <property name="interceptorNames">
            <list>
                <value>transactionInterceptor</value>
            </list>
        </property>
    </bean>  

    <!-- 配置DAO -->
    <bean id="userDao" class="com.bluesky.spring.dao.UserDaoImpl">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>
</beans>

第四种方式：使用tx标签配置的拦截器

<?xmlversion="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    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-2.5.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-2.5.xsd
          http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-2.5.xsd
          http://www.springframework.org/schema/txhttp://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:annotation-config />
    <context:component-scan base-package="com.bluesky" />

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

    <!-- 定义事务管理器（声明式的事务） -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*" propagation="REQUIRED" />
        </tx:attributes>
    </tx:advice>

    <aop:config>
        <aop:pointcut id="interceptorPointCuts"
           expression="execution(*com.bluesky.spring.dao.*.*(..))" />
        <aop:advisor advice-ref="txAdvice"
           pointcut-ref="interceptorPointCuts" />
    </aop:config>
</beans>

第五种方式：全注解

<?xmlversion="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    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-2.5.xsd
          http://www.springframework.org/schema/context
          http://www.springframework.org/schema/context/spring-context-2.5.xsd
          http://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-2.5.xsd
          http://www.springframework.org/schema/txhttp://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

    <context:annotation-config />
    <context:component-scan base-package="com.bluesky" />

    <tx:annotation-driven transaction-manager="transactionManager"/>

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

    <!-- 定义事务管理器（声明式的事务） -->
    <bean id="transactionManager"
        class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

</beans>

此时在DAO上需加上@Transactional注解，如下：

package com.bluesky.spring.dao;

import java.util.List;

import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import org.springframework.stereotype.Component;

import com.bluesky.spring.domain.User;

@Transactional
@Component("userDao")
public class UserDaoImpl extends HibernateDaoSupport implements UserDao {

    public List<User> listUsers() {
        return this.getSession().createQuery("fromUser").list();
    }
}