Missing Data from Spring Repository call-CodePudding

I have a Many-to-one relation with a Building object having multiple Room objects, but when i make the repository call for a building-object i get something like this:

{"id":3,"street":"Musterstreet","houseNumber":"10","postCode":"111111","city":"Heilbronn","rooms":[{},{}]}

where did i turn wrong that the Room-list doesnt show me any data of each Room-object, it clearly knows that there are 2 Room-objects in its list

my Entities look like this

@Entity
@Table(name = "buildings")
@NoArgsConstructor
@ToString(exclude = {"rooms"})
@Getter
@Setter
public class Building {

    @Id
    @GeneratedValue
    private Integer id;

    @NotNull
    @Column(nullable = false)
    private String street;

    @NotNull
    @Column(nullable = false)
    private String houseNumber;

    @NotNull
    @Column(nullable = false)
    private String postCode;

    @NotNull
    @Column(nullable = false)
    private String city;

    @OneToMany(fetch =  FetchType.EAGER, mappedBy = "building", cascade = CascadeType.ALL, orphanRemoval = true)
    private Set<Room> rooms = new HashSet<>();
}

and

@Entity
@Table(name = "room")
@NoArgsConstructor
@ToString(exclude = {"building"})
public class Room{

    @Id
    @GeneratedValue
    private Integer id;

    @NotNull
    @Column(nullable = false)
    private String roomName;

    @ManyToOne(fetch =  FetchType.EAGER)
    @JoinColumn(name = "building_id", nullable = false)
    private Building building; 
}

straight forward repo interface

public interface BuildingRepository extends JpaRepository<Building, Integer> {
    Optional<Building> findById(int id);
    Optional<Building> findByStreet(String street);
}

at last the controller method with the call

    @GetMapping("/buildings/{id}")
    public ResponseEntity<Building> getBuildingById(@PathVariable("id") Integer id) {
        Building building = buildingService.getBuildingById(id);
        return new ResponseEntity<>(building, HttpStatus.OK);
    }

what i want to do is to just work with the Building-object, so when i need a certain Room-object it can get extracted out of the list from the Building

CodePudding user response：

Your Room class is missing it's getters.

Add the following annotation:

@Getter

Spring uses Jackson by default, which generates the JSON by calling all public non-void methods which accept no arguments, or in other words, all accessors.

CodePudding user response：

As I see you don't have any getters and setters in your Room class, unlike your Building class, where you've set Lombok annotations. So Jackson (which spring-boot uses by default) may not be able to get field values when serializing an object to a JSON from your controller, though "rooms" collection has some entities.

Also I have to mention other problems:

it's considered bad practice to add FetchType.EAGER to your entity mapping, I strongly recommend reading Vlad Mihalcea articles, for example this one;
you might want to create some DTO classes to divide entity logic (like entity mapping) from de- / serialization logic.

CodePudding user response：

In your Room class, you have not mentioned getters.