Failed to find by foreign key - spring-boot

Question

I want to display all the rooms belong to the hospital of the current user
Class Room :
#Entity(name = "rooms")
#Table( name = "rooms",
uniqueConstraints = {
#UniqueConstraint(columnNames = "roomNumber")
})
public class Room {
#Id
#GeneratedValue(strategy = GenerationType.TABLE)
private Long idRoom;
private String roomNumber;
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(nullable = false, name = "idhospital")
private Hospital hospital;
#OneToMany(fetch = FetchType.LAZY, mappedBy = "room")
private Set<Bed> beds;
//getter and setter
Repository :
#Query("SELECT rm from rooms rm where rm.hospital=?1" )
List<Room> findRoomsByHospital(Hospital hospital);
Service :
List<Room> getRoomsByHospital(Hospital hospital);
ServiceImpl :
#Override
public List<Room> getRoomsByHospital(Hospital hospital) {
return roomRepository.findRoomsByHospital(hospital);
}
Controller :
#GetMapping("/display/room")
public ResponseEntity<List<Room>> getRoomsbyHospitalId(Authentication authentication) {
logger.info("Getting all RoomsByHospitalId from room table...Call getRoomsbyHospitalId ");
// to get the current user
Optional<User> user = userRepository.findByUsername(authentication.getName());
// to get the id of the hospital of the current user
Hospital hospital = user.get().getHospital();
logger.info("Data extracted from room table...");
//return ResponseEntity.ok(HospitalRooms);
return new ResponseEntity<>(roomService.getRoomsByHospital(hospital), HttpStatus.OK) ;
}
I had this error :
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help please!

Answer 1

I had the same problem. Solution in to add this notation #JsonIgnore here
#ManyToOne(fetch = FetchType.EAGER)
#JoinColumn(nullable = false, name = "idhospital")
private Hospital hospital;

Answer 2

Just NullPointerException doesn't really show where It's comming from, to help you debbug in the application.properties write the following:
spring.jpa.show-sql=true
spring.jpa.generate-ddl=true
spring.jpa.hibernate.ddl-auto=create
When running now It's going to show you how hibernate is handling your queries where are the null Objects or if it's getting the error before that. Here you are getting just an Id and It's being instance a HospitalModel
// to get the id of the hospital of the current user
Hospital hospital = user.get().getHospital();
Try just doing that instead:
Long hospital = user.get().getHospital();