JPA Native Query select and cast object

You might want to try one of the following ways:

• Using the method createNativeQuery(sqlString, resultClass)

  Native queries can also be defined dynamically using the EntityManager.createNativeQuery() API.

  String sql = "SELECT USER.* FROM USER_ AS USER WHERE ID = ?";
  
  Query query = em.createNativeQuery(sql, User.class);
  query.setParameter(1, id);
  User user = (User) query.getSingleResult();
  

• Using the annotation @NamedNativeQuery

  Native queries are defined through the @NamedNativeQuery and @NamedNativeQueries annotations, or <named-native-query> XML element.

  @NamedNativeQuery(
      name="complexQuery",
      query="SELECT USER.* FROM USER_ AS USER WHERE ID = ?",
      resultClass=User.class
  )
  public class User { ... }
  
  Query query = em.createNamedQuery("complexQuery", User.class);
  query.setParameter(1, id);
  User user = (User) query.getSingleResult();
  

You can read more in the excellent open book Java Persistence (available in PDF).

^{───────
NOTE: With regard to use of getSingleResult(), see Why you should never use getSingleResult() in JPA.}

The accepted answer is incorrect.

createNativeQuery will always return a Query:

public Query createNativeQuery(String sqlString, Class resultClass);

Calling getResultList on a Query returns List:

List getResultList()

When assigning (or casting) to List<MyEntity>, an unchecked assignment warning is produced.

Whereas, createQuery will return a TypedQuery:

public <T> TypedQuery<T> createQuery(String qlString, Class<T> resultClass);

Calling getResultList on a TypedQuery returns List<X>.

List<X> getResultList();

This is properly typed and will not give a warning.

With createNativeQuery, using ObjectMapper seems to be the only way to get rid of the warning. Personally, I choose to suppress the warning, as I see this as a deficiency in the library and not something I should have to worry about.

When your native query is based on joins, in that case you can get the result as list of objects and process it.

one simple example.

@Autowired
EntityManager em;

    String nativeQuery = "select name,age from users where id=?";   
    Query query = em.createNativeQuery(nativeQuery);
    query.setParameter(1,id);

    List<Object[]> list = query.getResultList();

    for(Object[] q1 : list){

        String name = q1[0].toString();
        //..
        //do something more on 
     }