hibernate4之后HibernateUtil类的编写

[code]public class HibernateUtil
{
    Session session=null;
    private static final SessionFactory sessionFactory;
    static
    {
        try
        {
            Configuration cfg = new Configuration().configure();
            ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(cfg.getProperties()).build();
            sessionFactory = cfg.buildSessionFactory(serviceRegistry);
        }
        catch (Throwable e)
        {
            throw new ExceptionInInitializerError(e);
        }
    }
    private HibernateUtil()
    {
    }
    public static SessionFactory getSessionFactory()
    {
        return sessionFactory;
    }
    public static Session getSession(){
    return sessionFactory.openSession();
    }
    public static void closeSession() {
        session.close();
    }
}