Question

I got a Set<UserDTO> collection in a not Hibernate object, and I got a User domain entity in Hibernate.

UserDTO contains less information about user (only id and name)

How can I select full Hibernate User Set/List from the DTO object?

Like this?

Set<UserDTO> setDTO = .....
String hql = "FROM User WHERE id IN (:userDTO )";
Query query = entityManager.createQuery(hql); 
query.setParameter("userDTO", setDTO);
return query.getResultList();

Thanks

Answer 1

Almost. But you’d have to extract the IDs in a separate collection first:

Set<Long> ids = new HashSet<Long>(setDTO.size());
for (UserDTO dto : setDTO) {
   ids.add(dto.getId());
}

Then proceed with the query, and pass the ids set as param.