No transactional entitymanager available in @PostConstruct

Question

Problem: entityManager.unwrap(SessionImplementor.class) cause no transactional entitymanager available exception.

Code:

@Component
public class HibernateEventWiring {

    @Autowired
    private ViewListener listener;

    @PersistenceContext(unitName = "config-punit")
    private EntityManager entityManager;

    @PostConstruct
    public void registerListeners() {
        SessionFactory sessionFactory = getSessionFactory();
        EventListenerRegistry registry = ((SessionFactoryImpl) sessionFactory).getServiceRegistry().getService(
                EventListenerRegistry.class);
        registry.getEventListenerGroup(EventType.PRE_UPDATE).appendListener(listener);
    }

    @Transactional
    private SessionFactory getSessionFactory() {
        // EXCEPTION: No transactional entitymanager available
        return entityManager.unwrap(SessionImplementor.class).getFactory(); 
    }
}

http://stackoverflow.com/q/14522691/1391249, http://stackoverflow.com/q/3423972/1391249 Additionally, you should not have inadvertently imported `javax.transaction.Transactional` (Java EE 7) in place of `org.springframework.transaction.annotation.Transactional`. — Tiny, Dec 19 '14 at 17:38
I assume you are using org.springframework.transaction.annotation.Transactional instead of javax.transaction.Transactional annotation. Is that true? — Andy Dufresne, Dec 19 '14 at 17:39

score 4 · Accepted Answer · edited May 23 '17 at 12:09

4

According to this excelent answer:

In the @PostConstruct (as with the afterPropertiesSet from the InitializingBean interface) there is no way to ensure that all the post processing is already done, so (indeed) there can be no Transactions.

As I see, you do not need a transaction nor an entity manager bean, but rather an entity manager factory bean. I think you should simply autowire the EntityManagerFactory and then unwrap the Hibernate SessionFactory from it.

@Autowired
private EntityManagerFactory entityManagerFactory;

@PostConstruct
public void registerListeners() {
    SessionFactory sessionFactory = entityManagerFactory.unwrap(SessionFactory.class);
    ...
}

edited May 23 '17 at 12:09

Community

1
1

answered Dec 19 '14 at 17:45

Lukas Risko

1,435
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`EntityManagerFactory` hasn't `unwrap` method. Update your answer to `((HibernateEntityManagerFactory) entityManagerFactory).getSessionFactory()` please – VB_ Dec 19 '14 at 19:31
Since version 2.1 of JPA there is the unwrap method on EntityManagerFactory class. ([javaee 7 javadoc](http://docs.oracle.com/javaee/7/api/javax/persistence/EntityManagerFactory.html#unwrap(java.lang.Class))) – Lukas Risko Dec 19 '14 at 19:40
I ended using a slight variation of your answer by using `entityManager.getEntityManagerFactory().unwrap(SessionFactory.class)` (which was inspired by this [answer](http://stackoverflow.com/a/17981359/177696)) since the `entityManager` was already being injected to the class by Spring. – Saïd Feb 26 '16 at 19:33

No transactional entitymanager available in @PostConstruct

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