使用Hibernate 4中的事务功能是否需要JTA管理器

Question

I'm following the tutorial here: http://www.javacodegeeks.com/2013/05/hibernate-4-with-spring.html to enable the "@Transactional annotation" in my Java web application but failed to make it run properly. Please advise if the JTA manager is really required, and why?

Please note that my webapp is based on Spring 3 + Hibernate 4 + Tomcat 7.

Background and my doubts:

My current web application uses my own custom class (implements HandlerInterceptor) to enable one-hibernatesession-per-request basis. Now I want to improve my application's maintainability by using the "@Transactional annotation" instead since that could save many lines of code.

According to my understanding, the @Transactional basically relies on the AOP concept to ensure the session (Hibernate session) is ready for use in the annotated method. This seems nothing to do with the JTA. But I wonder why can't I make it work on my webapp in Tomcat 7 (without JTA-provider).

After few searches on google, it looks like the JTA is required. This confuses me since this seems to be a very basic functionality that shouldn't have the complicated JTA-provider as a requirement.

Here is the error I got:

org.hibernate.HibernateException: No Session found for current thread
    org.springframework.orm.hibernate4.SpringSessionContext.currentSession(SpringSessionContext.java:97)
    org.hibernate.internal.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:988)
    ...

This is the code I use for testing:

....

@Autowired
org.hibernate.SessionFactory sessionFactory;

@Transactional
@RequestMapping(method = RequestMethod.GET)
protected String home() {
    Session session = sessionFactory.getCurrentSession(); // I expected the session is good to use now
    Province p = (Province) session.get(Province.class, 1L); // This causes no session found error :(


    return "home";
}

The spring XML:

....
<tx:annotation-driven/>
<context:component-scan base-package="..."/>

<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
    <property name="jndiName" value="java:comp/env/jdbc/..."/>
    <property name="lookupOnStartup" value="true"/>
    <property name="proxyInterface" value="javax.sql.DataSource"/>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.hbm2ddl.auto">update</prop>

            <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
        </props>
    </property>
</bean>

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

<bean id="persistenceExceptionTranslationPostProcessor" class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>
....

Thank you !

Answer 1

Just a speculation:

Your controller is defined in some kind of dispatcher-servlet.xml therefore seperates from the applicationContext in which < tx:annotation-driven/> is defined. The compoment you want to enhance with @Transactional need to be within the same context with < tx:annotation-driven> if I'm not mistaken. So the @Transactional does not work.

Answer 2

That was my silly mistake. The Spring uses CGLIB to proxy methods with @Transactional annotated and it seems like CBLIB can't enhance protected method.

protected String home() {

Changing this to

public String home() {

fixed the problem.