为什么我在定义时收到 IdClass 未定义错误？

Question

我有两个类，一个用户和一个本地用户。 LocalUser 对用户使用 FK 作为 PK。 当我尝试创建 LocalUserRepository 时，收到异常：java.lang.IllegalArgumentException：此 class [~.LocalUser] 未定义 IdClass。

我已经寻找了几个小时的答案，但我尝试过的一切都没有奏效。

@Entity( name = "User" )
@Table( name = "users" )
public class User implements Serializable
{
    @Id
    @GeneratedValue( strategy = GenerationType.IDENTITY, generator = "user_id_seq" )
    @Column( name = "id", updatable = false, columnDefinition = "BIGSERIAL" )
    private Long id;
    @Column( name = "given_name", nullable = false )
    private String givenName;
    @Column( name = "family_name" )
    private String familyName;
    @Enumerated( EnumType.STRING )
    @Column( name = "role", nullable = false, columnDefinition = "VARCHAR(32)" )
    private Role role;

    ...
}

---

@Entity( name = "LocalUser" )
@Table( name = "local_user" )
@IdClass( User.class )
public class LocalUser implements Serializable
{
    @Id
    @OneToOne( optional = false, orphanRemoval = true )
    @JoinColumn( name = "user_id", nullable = false, unique = true )
    private User user;
    @Column( name = "username", unique = true, nullable = false )
    private String username;
    @Column( name = "password", nullable = false )
    private String password;

    ...
}

---

public interface LocalUserRepo extends JpaRepository<LocalUser, User>
{
    @Query( "SELECT u.user FROM LocalUser u WHERE u.username = :username AND u.password = :password" )
    User getUser( String username, String password );
}

期望的结果是与此模式匹配的两个表：

用户

身份证 [PK]	给定的名称	姓	角色
1	例子	用户	用户

本地用户

user_id [PK,FK(用户)]	用户名	密码
1	示例用户	########

Answer 1

经过多次搜索，我终于设法完成了我正在尝试的事情。 我需要向 LocalUser 添加一个 ID，并将 map 添加给用户。 这是我所做的：

@Entity
@Table( name = "local_users" )
public class LocalUser
{
    @Id
    @GeneratedValue( strategy = GenerationType.IDENTITY )
    @Column( name = "user_id", nullable = false )
    private Long id;

    @MapsId
    @OneToOne( fetch = FetchType.EAGER, optional = false )
    @JoinColumn( name = "user_id", nullable = false, foreignKey = @ForeignKey( name = "local_users_user_id_fk" ) )
    private User user;

    @Column( name = "password", nullable = false )
    private String password;

    @Column( name = "username", nullable = false, unique = true )
    private String username;
}

---

@Entity
@Table( name = "users" )
public class User
{
    @Id
    @GeneratedValue( strategy = GenerationType.IDENTITY, generator = "user_id_seq" )
    @Column( name = "id", updatable = false, columnDefinition = "BIGSERIAL" )
    private Long id;
    @Column( name = "given_name", nullable = false )
    private String givenName;
    @Column( name = "family_name" )
    private String familyName;
    @Enumerated( EnumType.STRING )
    @Column( name = "role", nullable = false, columnDefinition = "VARCHAR(32)" )
    private Role role;

    ...

}

---

@Repository
public interface LocalUserRepo extends JpaRepository<LocalUser, Long>
{
    @Query( "SELECT u.user FROM LocalUser u WHERE u.username = :username AND u.password = :password" )
    User getUser( String username, String password );
}