传递给持久对象的分离实体：一个与ManyToOne关系的类与另外2个类

Question

1. 评论课

   @ManyToOne(fetch = FetchType.EAGER)
   @JoinColumn(name = "user_id")
   private User user;
   @ManyToOne(fetch = FetchType.EAGER)
   @JoinColumn(name = "image_id")
   private Image image;
   

2. 用户类别

   @OneToMany(mappedBy = "user", cascade = CascadeType.MERGE, fetch = 
   FetchType.EAGER)
   private List<Comment> comments = new ArrayList<>();
   

3. 图片类

   @OneToMany(mappedBy = "image",cascade = CascadeType.MERGE,fetch = 
   FetchType.EAGER)
   private List<Comment> comments = new ArrayList<Comment>();
   

4. 这些是我拥有的ManyToOne和OneToMany关系。由于“已将分离的实体传递给持久对象：ImageHoster.model.Comment”错误，因此无法持久保存Comment对象。

Answer 1

1. 我有点想通了。在我保留Comment对象的CommentRepository类中，我使用.merge而不是.persist

   EntityManager em = emf.createEntityManager（）; EntityTransaction transaction = em.getTransaction（）; 尝试{     transaction.begin（）;     em.merge（newComment）;

2. 而不是em.persist（newComment）;