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Hibernate using Query via Spring injection

Answer 1

A:

Services gets instantiated without the session factory via the default constructor. Afterwards, setSession() is called by Spring. Java tries to initialize the member query right after instantiation, when Spring has not yet called setSession(). You will either have to inject the session factory via a parametrized constructor or initialize the member queryin setSession().

tob 2010-08-07 22:00:15

Tried to instantiate query in setSessionFactory(). Got following exception 1: org.springframework.beans.MethodInvocationException: Property 'sessionFactory' threw exception; nested exception is org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here

Alkesh 2010-08-07 22:42:21

Answer 2

+1 A:

When a Service is instantiated, the query field is initialized. And at this time, the sessionFactory has not been injected, hence the NullPointerException.

But actually, the whole idea of initializing a Query at the Service creation time doesn't make much sense as queries are bound to the lifespan of a session. From the javadoc of Query:

Queries are executed by calling list(), scroll() or iterate(). A query may be re-executed by subsequent invocations. Its lifespan is, however, bounded by the lifespan of the Session that created it.

In other words, you should create a Query for each call, not once for all:

public class Services {
    protected SessionFactory sessionFactory;
    public void setSessionFactory(SessionFactory value) {
        sessionFactory = value;
    }

    public List foo() {
       Query query = sessionFactory.getCurrentSession().createQuery("....");
       ...
    }
}

Pascal Thivent 2010-08-07 22:41:43

Thanks Pascal, I didn't know that Queries are bound to session. This clears a lot for me.

Alkesh 2010-08-07 23:00:10

@Alkesh: You're welcome. And I can understand what you tried to do... but that's not how it works :)

Pascal Thivent 2010-08-07 23:09:58

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