Question

我有一个用例，父母的子女映射到同一个大孩子（已存在于数据库中）。当我坚持父母我得到

NonUniqueObjectException: A different object with the same identifier value .....

关系是：

A -> C   
A -> B -> C

A->C is m:m
B->C is m:m
A->B is 1:1

当C对象对A和B都相同时会出现问题。

 public class A {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;           

  @Valid
  @ManyToMany(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST,CascadeType.MERGE})
  @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
  @Fetch(FetchMode.SUBSELECT)
  @JoinTable(name = "a_c",joinColumns = @JoinColumn(name="a_id", referencedColumnName = "id"),
             inverseJoinColumns = @JoinColumn(name="c_id", referencedColumnName = "id"))
  private Set<C> cs;

  @Valid
  @OneToOne(cascade = CascadeType.ALL, orphanRemoval = true)
  @JoinColumn(name = "b_id")
  private B b;
 }


 public class B {

  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;           

  @Valid
  @ManyToMany(fetch = FetchType.EAGER, cascade = {CascadeType.PERSIST,CascadeType.MERGE})
  @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
  @Fetch(FetchMode.SUBSELECT)
  @JoinTable(name = "b_c",joinColumns = @JoinColumn(name="b_id", referencedColumnName = "id"),
            inverseJoinColumns = @JoinColumn(name="c_id", referencedColumnName = "id"))
  private Set<C> cs;
  }


 public class C {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;

  @JsonIgnore
  @Fetch(FetchMode.SELECT)
  @ManyToMany(fetch = FetchType.LAZY, mappedBy = "cs")
  public Set<A> as;

  @JsonIgnore
  @Fetch(FetchMode.SELECT)
  @ManyToMany(fetch = FetchType.LAZY, mappedBy = "cs")
  private Set<B> bs;
}

现在，如果我尝试使用具有相同主键A和B的C对象持久保存A，则会出现此异常。

一个hack是首先获取大孩子并设置子对象，但寻找其他选项。

当父母有同一个大孩子的孩子

0 个答案: