为什么我无法在连接表之间查找实体？

Question

我有两个实体：用户和电话。

用户实体：

@Getter
@Setter
@Accessors(chain = true)
@Entity
@Table(name = "user_table")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;
    @Column(name = "username", unique = true, nullable = false)
    @NonNull
    private String username;
    @Column(name = "firstname")
    @NonNull
    private String firstName;
    @Column(name = "lastname")
    @NonNull
    private String lastName;
    @Column(name = "age")
    @NonNull
    private Integer age;
    @Column(name = "email", nullable = false, unique = true)
    @NonNull
    private String email;
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "address_id", foreignKey = @ForeignKey(name = "fk_user_address_id"))
    private Address address;
    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @JoinColumn(name = "phone_number", foreignKey = @ForeignKey(name = "fk_user_phone_number"))
    private Phone phone;
}

电话实体：

@Getter
@Setter
@Accessors(chain = true)
@Entity
@Table(name = "phone_table")
public class Phone {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "phone_number", unique = true, nullable = false)
    @NonNull
    private String number;
}

我还创建了这些实体的 DTO 类。

@Data
@Accessors(chain = true)
public class CreateUserRequest {
    private Long userId;
    private String username;
    private String firstName;
    private String lastName;
    private Integer age;
    private String email;
    private CreatePhoneRequest phone;
    private CreateAddressRequest address;
}

@Data
@Accessors(chain = true)
public class UserResponse {
    private Long id;
    private String username;
    private String firstName;
    private String lastName;
    private String email;
    private int age;
    private PhoneResponse phone;
    private AddressResponse address;
    }
}

和

@Data
@Accessors(chain = true)
public class CreatePhoneRequest {
    private String phone;
}
@Data
@Accessors(chain = true)
public class PhoneResponse {
    private String phone;
}

然后

UserRepository extends JpaRepository<Long, User>

我

findUserByPhone_Number(String phonenumber

）

在服务中我制定了寻找用户的逻辑：

@Service
@RequiredArgsConstructor
public class UserServiceImpl implements UserService {
    private final UserRepository userRepository;
    private final PhoneServiceImpl phoneServiceImpl;

    //    ***********************************************************
    //    ******************* FIND USER BY PHONE ********************
    //    ***********************************************************
    @NonNull
    @Transactional(readOnly = true)
    @Override
    public UserResponse getUserByPhoneNumber(String phoneNumber) {
        return userRepository.findUserByPhone_Number(phoneNumber);
    } 
}

和用于发出请求的 UserController：

@RestController
@RequestMapping("/api/v1/users")
@RequiredArgsConstructor
public class UserController {
    private final UserServiceImpl userService;
    private final Logger log = LoggerFactory.getLogger(UserController.class);

    @GetMapping(value = "/phonenumber/{number}", produces = APPLICATION_JSON_VALUE)
    public UserResponse getUserByPhoneNumber(@PathVariable String number) {
        UserResponse user = userService.getUserByPhoneNumber(number);
        System.out.println(user);
        return user;
    }
}

我可以获取用户列表，我可以通过 ID 获取用户......但是当我尝试通过电话号码（连接表）获取用户时，我收到：

{
    "message": "Specified result type [com.app.apringlearn.app.ResponseRequest.UserResponse] did not match Query selection type [com.app.apringlearn.app.Enteties.User] - multiple selections: use Tuple or array"
}

Answer 1

只是让你的

getUserByPhoneNumber

返回

User

但不是

UserResponse

@NonNull
    @Transactional(readOnly = true)
    @Override
    public User getUserByPhoneNumber(String phoneNumber) {
        return userRepository.findUserByPhone_Number(phoneNumber);
    } 

并相应地更改所有链接类。

它应该按您的预期工作...