[FIXED] How to manage serializataion of Entities that have links to each other?

Issue

I have a Vote and a Restaurant entities, when I manage their relations with @JsonBackReference and @JsonManagedReference I have a problem.

If I serialize Restaurant - everything seems to be fine.

If I serialize Vote - fields with @JsonManagedReference are omitted. And I have this JSON:

{
    "id": 50,
    "voteDate": "2021-08-04"
}

I would appreciate if you could tell me, how I can serialize both objects without omitting fields and getting StackOverflow error.

Some entity's code are omitted for brevity:

@Entity
public class Vote extends AbstractBaseEntity {
    
    @ManyToOne
    @JsonBackReference
    private Restaurant restaurant;
    
    private LocalDate voteDate;
    
    @ManyToOne(fetch = FetchType.LAZY)
    @JsonBackReference
    private User user;
}

@Entity
@Getter
@Setter
@NoArgsConstructor
@ToString(exclude = {"votes", "dishes"})
public class Restaurant extends AbstractNamedEntity {

    String address;

    @OneToMany(mappedBy = "restaurant", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonManagedReference
    private List<Dish> dishes;

    @OneToMany(mappedBy = "restaurant", cascade = CascadeType.ALL, orphanRemoval = true)
    @JsonManagedReference
    private List<Vote> votes;
}

Solution

You have to convert entities to DTO objects. Add postfix Entity to the entities. And use names without postfix for DTO.

@Entity
class VoteEntity {


}

class Vote {

  private String voteDate;
  
  private String restaurantName;

}

Convert entities to DTO on the service level and do the serialization after that.

Answered By - v.ladynev