[Newbie] Replacing JDBC with Hibernate

fmarchioni · **Joined:** Wed Feb 14, 2007 4:49 am **Posts:** 7

Dear Hibernate users,
I'm going to replace a JDBC layer with Hibernate. I have tested the basic Hibernate examples now I'd like to know if I can avoid istantiating all Hibernate objects for every query/insert.

For example:
Is it good practice to put in a Singleton the SessionFactory and Configuration

Code:

public getInstance() {
                              if (config == null) {
                    config = new Configuration();
                              }
                            
                             if (sessionFactory == null) {
                    sessionFactory = config.buildSessionFactory();
                             }
}

Also, is there any advantage to keeping the Session object at Class level so that I don't open a new one for every query ?

Code:

public void getConnection {
           if (session == null) {
              session = sessionFactory.openSession();
          } 
          else {
             return session;
          }
}

Thanks for your help
Francesco

Cameron McKenzie · **Posted:** Tue Jul 22, 2008 5:58 am

You are definitely in the right directions.

The Session Factory is a very heavyweight objects, so you want to instantiate it in a Singleton type manner and make sure your application is only using one per database.

Sessions themselves are fairly lightweight though. You shouldn't have any guilty feelings about calling getSession whenever a Hibernate3 Session is needed.

By the way, feel free to check out my signature links for some further tutorials on how to use Hibernate. You might find them useful.

Hope this helps!

fmarchioni · **Joined:** Wed Feb 14, 2007 4:49 am **Posts:** 7

thanks a lot for the precise answer and for the links provided.
Regards
Francesco