用spring控制hibernate的session何时关闭

偏执的太偏执、 2021-09-14 00:26 306阅读 0赞

**用spring控制hibernate的session何时关闭**

在用spring管理hierbernate的事务我们一般都用TransactionProxyFactoryBean去配置我们的Service方法.

如.

<bean id="baseTxProxy" lazy-init="true" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" abstract="true">  
         <property name="transactionManager"><ref bean="transactionManager"/></property>  
         <property name="transactionAttributes">  
             <props>  
     <prop key="\*">PROPAGATION\_REQUIRED</prop>  
     <prop key="get\*">PROPAGATION\_REQUIRED,readOnly</prop>    
     <prop key="is\*">PROPAGATION\_REQUIRED,readOnly</prop>           
     <prop key="find\*">PROPAGATION\_REQUIRED,readOnly</prop>       
             </props>  
         </property>  
     </bean>  
  
         
  
<bean id="userService" parent="baseTxProxy">  
   <property name="target">  
    <bean class="com.dengyin.report.service.impl.UserServiceImpl" autowire="byName"/>  
   </property>  
</bean>  
  
<bean id="dailyReportService" parent="baseTxProxy">  
   <property name="target">  
    <bean class="com.dengyin.report.service.impl.DailyReportServiceImpl" autowire="byName"/>  
   </property>  
</bean>

我们可以想得到TransactionProxyFactoryBean是使用aop在Service方法之前open 一个session, begin Trans.在Service结束之后Commit Trans, close session.

但是我们使用spring的OpenSessionInViewFilter的时候就不能在Service方法后close session了. 应该是在Render page之后再关闭session的.所以我跟踪了spring的代码. 最后发现了spring是怎样做的(跟了好久,主要是上班偷偷摸摸搞的).

HibernateTransactionObject txObject = (HibernateTransactionObject) transaction;  
    if (txObject.getSessionHolder() == null) \{  
     Interceptor entityInterceptor = getEntityInterceptor();  
     Session newSession = (entityInterceptor != null ?  
       getSessionFactory().openSession(entityInterceptor) : getSessionFactory().openSession());  
     if (logger.isDebugEnabled()) \{  
      logger.debug("Opened new Session \[" + newSession + "\] for Hibernate transaction");  
     \}  
     txObject.setSessionHolder(new SessionHolder(newSession), true);  
    \}

txObject.getSessionHolder().setSynchronizedWithTransaction(true);  
    session = txObject.getSessionHolder().getSession();

这段代码是在进行Service之前的. 如果当前thread没有session的话就执行txObject.setSessionHolder(new SessionHolder(newSession), true);注意这里set了一个true值. 我们来看看txObject是一个什么东西.

private static class HibernateTransactionObject extends JdbcTransactionObjectSupport \{

private SessionHolder sessionHolder;

private boolean newSessionHolder;

public void setSessionHolder(SessionHolder sessionHolder, boolean newSessionHolder) \{  
    this.sessionHolder = sessionHolder;  
    this.newSessionHolder = newSessionHolder;  
   \}

public SessionHolder getSessionHolder() \{  
    return sessionHolder;  
   \}

public boolean isNewSessionHolder() \{  
    return newSessionHolder;  
   \}

public boolean hasTransaction() \{  
    return (this.sessionHolder != null && this.sessionHolder.getTransaction() != null);  
   \}

public void setRollbackOnly() \{  
    getSessionHolder().setRollbackOnly();  
    if (getConnectionHolder() != null) \{  
     getConnectionHolder().setRollbackOnly();  
    \}  
   \}

public boolean isRollbackOnly() \{  
    return getSessionHolder().isRollbackOnly() ||  
      (getConnectionHolder() != null && getConnectionHolder().isRollbackOnly());  
   \}  
\}

我们看看Service方法之后spring怎样close session的.

Session session = txObject.getSessionHolder().getSession();  
   if (txObject.isNewSessionHolder()) \{  
    if (logger.isDebugEnabled()) \{  
     logger.debug("Closing Hibernate Session \[" + session + "\] after transaction");  
    \}  
    SessionFactoryUtils.releaseSession(session, getSessionFactory());  
   \}  
   else \{  
    if (logger.isDebugEnabled()) \{  
     logger.debug("Not closing pre-bound Hibernate Session \[" + session + "\] after transaction");  
    \}  
    if (txObject.getSessionHolder().getPreviousFlushMode() != null) \{  
     session.setFlushMode(txObject.getSessionHolder().getPreviousFlushMode());  
    \}  
   \}  
   txObject.getSessionHolder().clear();

当txObject.isNewSessionHolder()的时候才会close   session.

总结:

所以当Service方法之间没有存在的session时spring会开一session,然后结束的时候close session.

当Service方法之间有存在的session的话,Service方法结束时并没有关闭   session.

**转自：[http://hi.baidu.com/injava/blog/item/e3778723d2218a46ac34defb.html][http_hi.baidu.com_injava_blog_item_e3778723d2218a46ac34defb.html]**

[http_hi.baidu.com_injava_blog_item_e3778723d2218a46ac34defb.html]: http://hi.baidu.com/injava/blog/item/e3778723d2218a46ac34defb.html