Hibernate: CRUD Generic DAO

Question

My web application has got a lot of service tables/entities, such as payment_methods, tax_codes, province_codes, etc.

Each time I add a new entity, I have to write a DAO. The thing is that, basically, they are all the same, but the only difference is the entity class itself.

I know that Hibernate tools can generate the code for me automatically but I can't use them now (don't ask why) so I'm thinking of a Generic DAO. There's a lot of literature about that but I can't put pieces together and make it work with Spring.

It's all about generics I think, it will have four basic methods:

• listAll
• saveOrUpdate
• deleteById
• getById

and that's all.

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Question:

What's the best practice for not re-inventing the wheel? Isn't there something ready to use, yet?

Answer 1

here's mine

@Component public class Dao{      @Resource(name = "sessionFactory")     private SessionFactory sessionFactory;      public <T> T save(final T o){       return (T) sessionFactory.getCurrentSession().save(o);     }       public void delete(final Object object){       sessionFactory.getCurrentSession().delete(object);     }      /***/     public <T> T get(final Class<T> type, final Long id){       return (T) sessionFactory.getCurrentSession().get(type, id);     }      /***/     public <T> T merge(final T o)   {       return (T) sessionFactory.getCurrentSession().merge(o);     }      /***/     public <T> void saveOrUpdate(final T o){       sessionFactory.getCurrentSession().saveOrUpdate(o);     }      public <T> List<T> getAll(final Class<T> type) {       final Session session = sessionFactory.getCurrentSession();       final Criteria crit = session.createCriteria(type);   return crit.list();     } // and so on, you shoudl get the idea 

and you can then access like so in service layer:

 @Autowired     private Dao dao;     @Transactional(readOnly = true)     public List<MyEntity> getAll() {       return dao.getAll(MyEntity.class);     }