使用 @manytoone 和 @.netomany 关系保存嵌套对象 hibernate

Question

I'have the following set up:

class Parent{
   @Id
   @GeneratedValue
   @Column(name = "id", nullable = false)
   private Integer id;

   @JsonManagedReference
   @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL, fetch = FetchType.LAZY, orphanRemoval = true)
   private Set<Child>;
}
class Child {
   @Id
   @GeneratedValue
   @Column(name = "id", nullable = false)
   private Integer id;

   @ManyToOne(cascade = {CascadeType.REMOVE}, fetch = FetchType.LAZY)
   @JoinColumn(name = "parent_id")
   @OnDelete(action = OnDeleteAction.CASCADE)
   @JsonBackReference
   private Parent parent;

   @OneToMany(mappedBy = "child",  cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
   @JsonManagedReference
   private Set<GrandChild>;
}
class GrandChild {
   @Id
   @GeneratedValue
   @Column(name = "id", nullable = false)
   private Integer id;

   @ManyToOne(cascade = CascadeType.REMOVE)
   @JoinColumn(name = "child_id")
   @JsonBackReference
   private Child child;
}

All of the classes has the following annotations:

@Builder
@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@With
@Entity
@Table(name='each table name')

When I send a Json containing the Parent inside Childs and inside GrandChilds I can't save it, cause the parent_id column in the child cannot be null. Then I tried the approach to save the parent first and then just add the set of Childs, but the same thing is happening with GrandChild (child_id cannot be null). Is there a way I can configure the hibernate to first save the parent, retrieve the ID, set it to the Child then save the child and then set ChildId to the GrandChild? I started with saving first the Parent and then then set the set of childs to it and save it again (making update) and this was working, but when I add the GrandChilds it stops working. I can't (without polluting the objects) make same thing for the GrandChilds cause I'll not have the connection which is where.

Answer 1

My setup is ok, but I was using immutable objects when setting parent to the Child object and Child to GrandChild. When I changed from with to set it started working