3 ways of integrating Hibernate and Spring

There are many ways to integrate Hibernate Data Access Objects (DAOs) with the Spring Framework. The Spring 2.5 documentation describes three possible solutions how Spring supports those DAOs. But which is the right way to go nowadays? Let's compare the three variants:

1. Let your concrete DAO class extend HibernateDaoSupport. This base class has to be configured with a SessionFactory and gives access to Hibernate Sessions and a HibernateTemplate.
2. Directly injecting a HibernateTemplate into your DAO class. You don't have to extend any framework class. The HibernateTemplate gives access to many general purpose dao methods. This is o.k. for many cases but accessing the hibernate session directly from the HibernateTemplate is verbose. You have to pass anonymous callbacks to get access to the session.
   On the other side the HibernateTemplate is handy when it comes to automatic handling of the hibernate session management (e.g. binding the session to the current Transaction) but as you'll see this is no longer needed in Hibernate 3. It also converts any Hibernate or SQL related Exception into a corresponding DataAccessException, which is very helpful.
   
3. Directly injecting the Hibernate SessionFactory into your DAO class. Your DAO won't have dependancies on any class from the Spring Framework. Since Hibernate 3 is capable of binding the Session to a preset Context (e.g. Thread or Transaction) the HibernateTemplate is no longer needed.

So which of these variants should be preferred? If you use Hibernate 3 then you should stick with the third variant. Take a look at the Hibernate property current_session_context and Session#getCurrentSession() (see Hibernate documentation for details).
As you can read in the Javadoc of HibernateTemplate the Spring Team confirms this:

NOTE: As of Hibernate 3.0.1, transactional Hibernate access code can also be coded in plain Hibernate style. Hence, for newly started projects, consider adopting the standard Hibernate3 style of coding data access objects instead, based on SessionFactory.getCurrentSession().

You may ask how you can get DataAccessExceptions with this variant? This is quite simple: just annotate your DAOs with @Repository and include this Spring Bean into you ApplicationContext: