Sample.java

  @PersistenceContext(unitName = "default") // @PersistenceContext() と同じ
  private EntityManager entityManager;

  @RequestMapping(path = "/test", method = RequestMethod.GET)
  public ResponseEntity<?> test() {
    var ret =
        entityManager.createNativeQuery("select * from t_employee", Employee.class).getResultList();
    return ResponseEntity.ok(Map.of("result", ret));
  }

// windows
// curl -X GET http://localhost:8080/test