Question

我正在试图制作带有物品的购物车。用户有多个项目，所以我这样做：我有一个@Entity @Table类Item，它实现了Serializable

private User user;

...

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Long getId() {
    return id;
}
public void setId(Long id) {
    this.id = id;
}


@OneToMany(cascade = ALL, fetch = FetchType.EAGER, mappedBy = "items")
@Column(nullable = true, updatable = false)
public User getUser() {
    return user;
}

并在User.java中（@Entity @Table实现Serializable）：

private List<Item> items; 
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

...

@ManyToOne
public List<Item> getItems() {
    return items;
}

public void setItems(List<Item> items) {
    this.items = items;
}

我得到的是这个错误：

Caused by: org.hibernate.AnnotationException: Illegal attempt to map a non collection as a @OneToMany, @ManyToMany or @CollectionOfElements: org.auction.model.Item.user"}}

Answer 1

你的注释混淆了，@ OneToMany是集合的集合

在Items类

中

 @ManyToOne(cascade = ALL, fetch = FetchType.EAGER)
 @Column(nullable = true, updatable = false)
  public User getUser() {
   return user;
  }

在用户类中，您将拥有OneToMany

@OneToMany(mappedBy = "user")
public List<Item> getItems() {
   return items;
}

org.hibernate.AnnotationException映射错误

1 个答案: