将本机查询JPA的结果集设置为POJO会引发Null指针异常

Question

I want to convert the resultset List to entity class. My Native query:

 @Query("select type,name,latitude,longitute,111.045* DEGREES (ACOS(COS(RADIANS(:latitude))*COS (RADIANS(latitude))*COS(RADIANS(:longitute) - RADIANS (longitute))"
            + "+SIN (RADIANS (:latitude))*SIN (RADIANS(latitude)))) As distance_in_km from Place ORDER BY distance_in_km ")
     List<Object[]> findBylattitudeAndlongitute(@Param("latitude") double latitude ,@Param("longitute") double longitute );

My entity class:

@EnableCaching
@Entity
@Table(name = "PLACEDETAILS_H")
public class Place {

    public Place() {
    }   
    private String type;
    private String name;
    private String Code;
    private String Name;
    private String Code1;   
    private String Name2;
    private double latitude;
    private double longitute;

}

service class:

 List<Object[]>  places = Repository.findBylattitudeAndlongitute(latitude, longitute);  
Place place = null;
             for (Object[] pla:places)
             {
                 place.setType((String) pla[0]);
          place.setName((String) pla[1]);   
             }

Since the distance_in_km in not a variable in place entity, I am unable to map the resultset directly.The query executed successfully and Im getting response List.

I tried setting the pla[0] to type but It shows null pointer exception. help me to resolve this issue.

Answer 1

1. You need to add the following transient column:

    @Transient private Double distance_in_km; 

2. You need to change your Spring Data @Query to a Hibernate native query instead:

    String sql = "select type as {p.type}, name as {p.name}, latitude as {p.latitude}, longitute as {p.longitute},111.045* DEGREES (ACOS(COS(RADIANS(:latitude))*COS (RADIANS(latitude))*COS(RADIANS(:longitute) - RADIANS (longitute))" + "+SIN (RADIANS (:latitude))*SIN (RADIANS(latitude)))) As {p.distanceInKm} from Place p ORDER BY {p.distanceInKm} "; List<Place> places = (List<Place>) session.createSQLQuery(sql) .setParameter("latitude", latitude) .setParameter("longitute", longitute) .addEntity("p", Place.class).list();