Spring配置事务在DAO层和SERVICE层

【转载自http://www.blogjava.net/hk2000c/archive/2007/11/01/157508.html】
【感谢原作者：hk2000c】
Spring通过AOP实现声明式事务管理。通常通过TransactionProxyFactoryBean设置Spring事务代理。我们需要一个目标对象包装在事务代理中。这个目标对象一般是一个普通Java对象的bean。当我们定义TransactionProxyFactoryBean时，必须提供一个相关的 PlatformTransactionManager的引用和事务属性。 事务属性含有上面描述的事务定义。
PlatformTransactionManager：
HibernateTransactionManager需要一个SessionFactory的引用
JtaTransactionManager
一．把事务放置在了DAO层：

<!—hibernateTransactionManager-->
<bean id="transactionManager"
       class="org.springframework.orm.hibernate3.HibernateTransactionManager">
       <property name="sessionFactory">
              <ref local="sessionFactory" />
       </property>
</bean>
<!—DAO层接口实现-->
<bean id="companyDAOTarget"
       class="com.vstsoft.querycompany.dao.impl.CompanyDAOImpl">
       <property name="sessionFactory">
              <ref local="sessionFactory" />
       </property>
</bean>
<!—spring对DAO层的事务代理-->
<bean id="companyDAOProxy"
       class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
       <property name="transactionManager">
              <ref bean="transactionManager" />
       </property>
       <property name="target">
              <ref local="companyDAOTarget" />
       </property>
       <property name="transactionAttributes">
              <props>
              <prop key="insert*">PROPAGATION_REQUIRED</prop>
              <prop key="delete*">PROPAGATION_REQUIRED</prop>
              <prop key="find*">
              PROPAGATION_REQUIRED,readOnly
              </prop>
              </props>
       </property>
</bean>
<!—业务层接口实现，把DAO注入到Service里面-->
<bean name="companyManageTarget"
       class="com.vstsoft.querycompany.service.impl.CompanyManageTarget">
       <property name="companyDAO">
              <ref bean="companyDAOProxy" />
       </property>
</bean>
<!—spring对Service层的代理-->
<bean id="companyManageProxy"
       class="org.springframework.aop.framework.ProxyFactoryBean">
       <property name="proxyInterfaces">
              <value>com.vstsoft.querycompany.service.CompanyManage</value>
       </property>
       <property name="target">
              <ref bean="companyManageTarget" />
       </property>
</bean>
<!—配置struts访问，把service层注入到action里面-->
<bean name="/company"
       class="com.vstsoft.querycompany.web.action.CompanyAction" singleton="false">
       <property name="companyManage">
              <ref local="companyManageProxy" />
       </property>
</bean>

二．把事务放置在了Service层：

<!—jtaTransactionManager-->
<bean id="jtaTransactionManager"
       class="org.springframework.transaction.jta.JtaTransactionManager" />
<!—DAO层接口实现-->
<bean id="companyDAOTarget"
       class="com.vstsoft.querycompany.dao.impl.CompanyDAOImpl">
       <property name="sessionFactory">
              <ref local="sessionFactory" />
       </property>
</bean>
<!—spring对DAO层的代理-->
<bean id="companyDAOProxy"
       class="org.springframework.aop.framework.ProxyFactoryBean">
       <property name="proxyInterfaces">
              <value>com.vstsoft.querycompany.dao.CompanyDAO</value>
       </property>
       <property name="target">
              <ref bean="companyDAOTarget" />
       </property>
</bean>
<!—业务层接口实现，把DAO注入到Service里面-->
<bean name="companyManageTarget"
       class="com.vstsoft.querycompany.service.impl.CompanyManageTarget">
       <property name="companyDAO">
              <ref bean="companyDAOProxy" />
       </property>
</bean>
<!—spring代理业务层的事务管理-->
<bean id="companyManageProxy"
       class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
       <property name="transactionManager">
              <ref local="jtaTransactionManager" />
       </property>
       <property name="transactionAttributes">
              <props>
                     <prop key="set*">PROPAGATION_REQUIRED</prop>
                     <prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>
              </props>
       </property>
       <property name="target">
              <ref bean="companyManageTarget" />
       </property>
</bean>
<!—配置struts访问，把service层注入到action里面-->
<bean name="/company"
       class="com.vstsoft.querycompany.web.action.CompanyAction" singleton="false">
       <property name="companyManage">
              <ref local="companyManageProxy" />
       </property>
</bean>

例如：在service层的接口实现CompanyManageImpl里面有个setData方法：按顺序执行对数据库的数据查询，数据删除，数据插入数据库，如果哪一步出异常（运行时异常），以上三个操作都将事务回滚。