java - @ManyToOne 和@OneToOne 在同一实体上

Question

假设我们有这两个实体:

@Entity
class Address{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long bookId;

   @ManyToOne
   @OneToOne
   private User user;

   ...
}

@Entity
class User{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long userId;

   @OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
   private List<Address> addresses;

   @OneToOne(mappedBy = "user", cascade = CascadeType.ALL)
   private Address principalAddress;

   ...
}

如您所见，我在 Address 类中的用户实体顶部有两个注释(@ManyToOne 和@OneToOne)。关键是，我知道这是错误的，但我不知道如何正确映射它。设计有问题吗？逻辑是用户有一个地址列表和一个且唯一的主要地址。我怎样才能正确映射它？有什么想法吗？

Answer 1

在这种情况下，您可以做的是标记“isPrincipalAddress”。

@Entity
class Address{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long bookId;

   private Boolean isPrincipalAddress;

   @ManyToOne
   private User user;

   ...
}

@Entity
class User{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long userId;

   @OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
   private List<Address> addresses;

   ...
}