Hibernate:@onetomany:从“many”端删除实体导致EntityNotFoundException

Question

我有以下实体：

@Entity
public static class Parent {
    @Id
    @GeneratedValue
    private Long id;

    String st;

    @OneToMany(mappedBy = "parent")
    Set<Child> children = new HashSet<>();
    // get,set 
}

@Entity
public static class Child {


    @Id
    @GeneratedValue
    private Long id;

    String st;

    @ManyToOne()
    private Parent parent;
    //get,set
  }

null

null

但看起来像是黑客。

所以，1。我做错了什么？看起来，直接删除子实体
2是正确的。有没有更优雅的方法来处理这个？

可复制的例子：

@Autowired
PrentCrud parentDao;

@Autowired
ChiildCrud childDao;
@PostConstruct
public void doSomething() {

    LogManager.getLogger("org.hibernate.SQL").setLevel(Level.DEBUG);


    Parent p = new Parent();
    p.setSt("1");
    Child e = new Child();
    e.setParent(p);
    e.setSt("c");
    p.getChildren().add(e);
    Parent save = parentDao.save(p);
    e.setParent(save);
    childDao.save(e);
    Parent next = parentDao.findAll().iterator().next();
    next.setSt("2");
    next.getChildren().size();
    childDao.deleteAll();
    next.getChildren().clear();
    if (next.getChildren() instanceof PersistentSet) { // this is hack, not working without
        ((Map)((PersistentSet) next.getChildren()).getStoredSnapshot()).clear();
    }
    parentDao.save(next); // exception is thrwn here without hack
    System.out.println("Success");

}

Answer 1

您尝试过将fetch类型更改为eager吗？关系的默认值onetomany:LAZY manytoone:eary manytomany:LAZY onetoone:eary

也许它被缓存是因为fetch方法