我在与@OneToMany关系链接的用户实体上有一个角色实体列表。当我更改用户实体上的列表时，即更改角色，Hibernate会删除旧角色并根据需要添加新角色。但是，外键字段在角色实体上设置为 null。
您能否解释为什么 foregign 键字段为空，以及我将如何更改它以便在更新时被拾取？
用户.java
@SerializedName("userrole")
@Expose
@OneToMany(mappedBy = "user", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
private List<Role> userRoles = new ArrayList<Role>();
角色.java
@ManyToOne
@JoinColumn(name = "user")
private User user;
表前
+----+------+------------------------+
| id | role | user |
+----+------+------------------------+
| 1 | 0 | digby.tyson@gmail.com |
| 2 | 1 | digby.tyson@gmail.com |
| 3 | 2 | digby.tyson@gmail.com |
| 4 | 3 | digby.tyson@gmail.com |
| 5 | 4 | digby.tyson@gmail.com |
| 6 | 5 | digby.tyson@gmail.com |
| 7 | 6 | digby.tyson@gmail.com |
| 8 | 7 | digby.tyson@gmail.com |
| 9 | 5 | ronny.polley@gmail.com |
| 10 | 6 | ronny.polley@gmail.com |
| 11 | 7 | reed.robert@gmail.com |
+----+------+------------------------+
表后
+----+------+------------------------+
| id | role | user |
+----+------+------------------------+
| 9 | 5 | ronny.polley@gmail.com |
| 10 | 6 | ronny.polley@gmail.com |
| 11 | 7 | reed.robert@gmail.com |
| 12 | 0 | NULL |
| 13 | 1 | NULL |
| 14 | 2 | NULL |
| 15 | 5 | NULL |
| 16 | 6 | NULL |
| 17 | 7 | NULL |
+----+------+------------------------+
Hibernate操作
Hibernate: select userroles0_.user as user3_2_0_, userroles0_.id as id1_1_0_, userroles0_.id as id1_1_1_, userroles0_.role as role2_1_1_, userroles0_.user as user3_1_1_ from role userroles0_ where userroles0_.user=?
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: insert into role (role, user) values (?, ?)
Hibernate: update user set first_name=?, last_name=?, middle_name=?, organisation_id=? where email=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
Hibernate: delete from role where id=?
更新
根据注释中的请求调用数据库的方法
@Override
@Transactional
public User update(User user) throws UserNotFoundException {
String updatedUserEmail = user.getEmail();
if (userRepository.findByEmail(updatedUserEmail) == null)
throw new UserNotFoundException();
return userRepository.save(user);
}
@Transactional
public interface UserRepository extends CrudRepository<User, Long> {
提前感谢您的任何帮助。
映射是正确的，现在您要实现的是，当从用户中删除角色时，您希望删除该角色（orphanRemoval = true）。
这是一个双向关联，因此您需要做的是在两端进行更改以保持对象模型的一致性：
// remove role from user one-to-many
user.getUserRoles().remove(roleToBeDeleted);
// remove the many-to-one association
roleToBeDeleted.setUser(null);
我用EntityManager并使用Hibernate做了这个，它似乎工作正常。您是否将旧角色从列表中删除
用户：
@Entity
public class User {
@Id private String email;
@OneToMany(mappedBy = "user", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
private List<Role> userRoles = new ArrayList<Role>();
角色：
@Entity
public class Role {
@Id @GeneratedValue private Long id;
@ManyToOne
private User user;
运行方式为：
User u = em.find(User.class, "test@test.com");
Role e = new Role();
e.setUser(u);
u.getUserRoles().remove(0);
u.getUserRoles().add(e);
em.merge(u);
给我：
Hibernate: insert into Role (user_email, id) values (?, ?)
Hibernate: delete from Role where id=?
Hibernate: select * from role
在角色表中只有一行：
[2, test@test.com]
