java 第二次调用方法后，Hibernate Session 在 spring 事务中关闭

Hibernate Session is closed in spring transaction after calling method second time

提问by Akhilesh

First of all I am a beginner in spring.I have created a simple Spring service that has DAO injected and transaction is managed by HibernateTransactionManager of spring, like as below.(And transaction configuration is used using annotations )

首先，我是spring的初学者。我创建了一个简单的Spring服务，注入了DAO，事务由spring的HibernateTransactionManager管理，如下所示。（使用注释使用事务配置）

@Service(value="daopowered")
public class UserServiceImplDao implements UserService
    {
    @Inject
    private UserDao userDao;


    @Override
    @Transactional
    public User autheticate( String userId, String password )
    {
    return userDao.findByIdAndPassword(userId, password);
    } 

My transaction configuration is following

我的交易配置如下

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

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

Now the problem is when I call authenticate method first time using some controller then it works fine ( does DB operations successfully) but after calling it again second time hibernate session is closed exception is coming ? Please guide me what I am doing it wrong or how to handle this scenario ? Why wont spring opens a new transaction when I call this method second time ?

现在的问题是，当我第一次使用某个控制器调用身份验证方法时，它工作正常（数据库操作是否成功），但是在第二次休眠会话关闭时再次调用它后异常即将到来？请指导我我做错了什么或如何处理这种情况？当我第二次调用此方法时，为什么 spring 不会打开一个新事务？

Exception Trace:

异常跟踪：

2013-05-22T21:04:18.041+0530 DEBUG [14208212-2] lerExceptionResolver Resolving exception from handler [com.akhi.store.controller.HomeController@5d9d277e]: org.springframework.orm.hibernate3.HibernateSystemException: Session is closed!; nested exception is org.hibernate.SessionException: Session is closed!
2013-05-22T21:04:18.044+0530 DEBUG [14208212-2] tusExceptionResolver Resolving exception from handler [com.akhi.store.controller.HomeController@5d9d277e]: org.springframework.orm.hibernate3.HibernateSystemException: Session is closed!; nested exception is org.hibernate.SessionException: Session is closed!
2013-05-22T21:04:18.044+0530 DEBUG [14208212-2] lerExceptionResolver Resolving exception from handler [com.akhi.store.controller.HomeController@5d9d277e]: org.springframework.orm.hibernate3.HibernateSystemException: Session is closed!; nested exception is org.hibernate.SessionException: Session is closed!
2013-05-22T21:04:18.046+0530 DEBUG [14208212-2] et.DispatcherServlet Could not complete request
org.springframework.orm.hibernate3.HibernateSystemException: Session is closed!; nested exception is org.hibernate.SessionException: Session is closed!
    at org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:658)
    at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.convertHibernateAccessException(AbstractSessionFactoryBean.java:245)
    at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.translateExceptionIfPossible(AbstractSessionFactoryBean.java:224)
    at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58)
    at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
    at com.sun.proxy.$Proxy28.findByIdAndPassword(Unknown Source)

EDIT: The DAO code

编辑：DAO 代码

@Repository
public class UserDaoImpl extends GenericHibernateDAO<User, Long>
                                implements
                                UserDao
    {

    @Override
    public User findByIdAndPassword( String id, String password )
    {

    Criteria crit = getSession().createCriteria(User.class).add(Restrictions.eq("userId",
                                            id)).add(Restrictions.eq("password",
                                                         password)).setMaxResults(1);
    List<?> list = crit.list();

    if (list.size() > 0)
        return (User) list.get(0);
    else
        return null;
    }

and getSession() implementation is

和 getSession() 实现是

protected Session getSession() {
    if (session == null) {
        session = sessionFactory.getCurrentSession();
    }

    return session;
}

Also the abstract DAO class has sessionfactory injected

抽象的 DAO 类也注入了 sessionfactory

public abstract class GenericHibernateDAO<T, ID extends Serializable>
        implements GenericDAO<T, Long> {
    private Class<T> persistentClass;

    protected Session session;

    @Autowired
    private SessionFactory sessionFactory;

回答by Sark

Your ObjectDao need a SessionFactory and the annotation Transaction. Something like this :

您的 ObjectDao 需要一个 SessionFactory 和注释事务。像这样的事情：

@Component
public class userDao{
       @AutoWired
       private SessionFactory sessionFactory;


       @Transactional
       public User findByIdAndPassword(String id , String password){
             ....
       }

       {getters and setters}

} 

Dont do that :

不要那样做：

protected Session getSession() {
    if (session == null) {
        session = sessionFactory.getCurrentSession();
    }

    return session;
}

just return the current session , the Transactional annotation is responsible for opening and closing sessions , like this :

只需返回当前会话，事务注释负责打开和关闭会话，如下所示：

protected Session getSession() {
    return  sessionFactory.getCurrentSession();
}