I'm new to Spring and trying to implement Generic DAO like in this article http://www.ibm.com/developerworks/library/j-genericdao/ . I have couple of entities - ConcreteEntity1 and ConcreteEntity2. Also, I have classes
public interface GenericDao<T extends Serializable> {
public T get(long id);
public List<T> get(String hql);
public void remove(T persistentObject);
public void add(T entity);
}
and
@Repository("hibGenericDao")
public class HibGenericDaoImpl<T extends Serializable> implements GenericDao<T> {
@Autowired
private SessionFactory sessionFactory;
private Class<T> type;
public HibGenericDaoImpl(Class<T> type) {
this.type = type;
}
/** {@inheritDoc} */
@Override
public T get(long id) {
T entity;
try (Session session = sessionFactory.getCurrentSession()) {
entity = session.get(type, id);
}
return entity;
}
/** {@inheritDoc} */
@Override
public List<T> get(String hql) {
List<T> entityList;
try (Session session = sessionFactory.getCurrentSession()) {
Query query = session.createQuery(hql);
entityList = query.list();
}
return entityList;
}
/** {@inheritDoc} */
@Override
public void remove(T persistentObject) {
try (Session session = sessionFactory.getCurrentSession()) {
session.delete(persistentObject);
}
}
/** {@inheritDoc} */
@Override
public void add(T entity) {
try (Session session = sessionFactory.getCurrentSession()) {
session.saveOrUpdate(entity);
}
}
}
Now I'm trying to write service layer, and I want to autowire HibGenericDaoImpl<ConcreteEntity1>
where field type
contains ConcreteEntity1.class
. Could you please say how to perform it without XML?
If you are already using spring, you can use the GenericTypeResolver utility class, as shown in this SO answer: How to get a class instance of generics type T
You should be able to do something like:
this.type = (Class<T>) GenericTypeResolver.resolveTypeArgument(getClass(), GenericDao.class);