TypedQuery instead of normal Query in JPA

Question

Is it possible to write this Query as a TypedQuery and let the two Long\'s run into a Object with two public Long fields inside.

    Query q = em.createQuery(
           


        

Answer 1

JPA has a feature just for this - constructor expressions:

Query q = entityManager.createQuery("SELECT NEW com.example.DTO( c.id, COUNT(t.id)) FROM ...");
List dtos = q.getResultList();

Your DTO class can be a POJO. All it will need is a public constructor accepting 2 Longs. Please note that you have to provide a fully qualified name of your class after the NEWoperator.