java - @JoinColumnS 涉及一对一关系中的 EAGER 获取

Question

我在两个类之间有 @OneToOne 关系，其结构如下:

用户:

@Getter
@Setter
@NoArgsConstructor
@Entity
public class User implements Serializable {

    @Id
    private Integer id;
    private String login;
    private String password;
    private String name;
    private String address;
    private Boolean active;
    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumns( {@JoinColumn(name = "userDetailId", referencedColumnName="id",  insertable=false, updatable=false),
            @JoinColumn(name = "address", referencedColumnName="location", insertable=false, updatable=false)} )
    private UserDetail userDetail;

}

用户详细信息:

@Getter
@Setter
@NoArgsConstructor
@Entity
public class UserDetail implements Serializable {
    @Id
    private Integer id;
    private String location;

}

在我的 userRepository 中，我使用entityGraph 在 userDetail 查询中获取左连接

@Repository
public interface UserRepository extends JpaRepository<User, Integer> {
     @EntityGraph(attributePaths = {"userDetail"})
     List<User> findAll();
}

当我调用 findAll() 时，我希望有一个左连接查询，因此 Hibernate 会使用左连接进行查询，并针对用户表中的每一行对 user_detail 进行查询，如下所示:

Hibernate: 
    select
        user0_.id as id1_0_0_,
        userdetail1_.id as id1_1_1_,
        user0_.active as active2_0_0_,
        user0_.address as address3_0_0_,
        user0_.login as login4_0_0_,
        user0_.name as name5_0_0_,
        user0_.password as password6_0_0_,
        user0_.user_detail_id as user_det7_0_0_,
        userdetail1_.location as location2_1_1_ 
    from
        user user0_ 
    left outer join
        user_detail userdetail1_ 
            on user0_.user_detail_id=userdetail1_.id 
            and user0_.address=userdetail1_.location
Hibernate: 
    select
        userdetail0_.id as id1_1_0_,
        userdetail0_.location as location2_1_0_ 
    from
        user_detail userdetail0_ 
    where
        userdetail0_.id=? 
        and userdetail0_.location=?

如何禁用 use_detail 查询？ 我已经尝试过

@Fetch(FetchMode.JOIN)
@LazyToOne(LazyToOneOption.NO_PROXY)

当我使用单个主键 @JoinColumn 而不是 @JoinColumnS 时，hibernate 仅使用左连接进行一个查询，就像我一样，但我需要多个键。 poc的链接here

感谢您阅读我的文章

Answer 1

这并不像使用@OneToMany(默认情况下是Lazy)或@ManyToOne那样容易

一个可能的解决方案是仅拥有可能为空的一对一引用的实体，并按需获取该实体。

https://stackoverflow.com/a/60108442/10218258给出了很好的解释。