名为“default reference”的多个反向引用属性

Question

我在一个类中有多个反向引用类。由于我对它们使用了@jsonBackReference，所以我得到了一个错误。我为这些类分配了@JSONIdentityInfo注释，但仍然得到相同的错误。

public class X implements Serializable {
  ....
  //bi-directional many-to-one association to Booking
  @ManyToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "xxA", nullable = false)
  @JsonBackReference
  private A a;

  //bi-directional many-to-one association to Client
  @ManyToOne(fetch = FetchType.EAGER)
  @JoinColumn(name = "xxB", nullable = false)
  @JsonBackReference
  private B b;
  ...getters setters
}

@JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "@id")
public class B implements Serializable {
  ........ 
  //bi-directional many-to-one association to BookedClient
  @OneToMany(mappedBy = "b", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
  @JsonManagedReference
  private List < X > xxB;
  ........ getters setters
}


@JsonIdentityInfo(generator = ObjectIdGenerators.IntSequenceGenerator.class, property = "@id")
public class A implements Serializable {
  ........
  //bi-directional many-to-one association to BookedClient
  @OneToMany(mappedBy = "a", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
  @JsonManagedReference
  private List < X > xxA;
  ........ getters setters
}

错误：

Answer 1

根据Jackson的javadoc,@JSONManagedReference和@JSONBackReference都接受一个将它们绑定在一起的名称值：

  @JsonBackReference("a")
  private A a;

  @JsonManagedReference("a")
  private List < X > xxA;