問題是：當我使用 JpaRepository 并使用一種方法通過用戶名獲取用戶時，如下代碼：public interface UserRepository extends JpaRepository<User, Integer> {    @Query(value = "select * from users where username = :name", nativeQuery = true)    User findUserByName(@Param("name") String name);}這是實體：@Entity@Table(name = "users")@Datapublic class User {    @Id    @GeneratedValue(strategy = GenerationType.IDENTITY)    private Integer id;    @Column(name = "username", nullable = false, unique = true)    private String username;    @Temporal(TemporalType.TIMESTAMP)    @Column(name = "joined_date", nullable = false, unique = true)    @CreatedDate    private Date joinedDate;    @Column(name = "password")    private String password;    @Column(name = "bio")    private String bio;    @Column(name = "email", nullable = false, unique = true)    private String email;}   這是控制器：@RestController@RequestMapping("/u")public class UserController {    @Autowired    private UserRepository repo;    ....    @GetMapping("/{name}")    public ResponseEntity<User> getUsernameAndPasswordByName(@PathVariable("name") String name) {        User user = repo.findUserByName(name);        if(user == null) {            return new ResponseEntity(HttpStatus.BAD_REQUEST);        }        return new ResponseEntity<User>(user, HttpStatus.OK);    }}這是從數據庫獲取所有用戶時 JSON 的全部數據：當我從名稱（網址：）獲取用戶時localhost/u/{username}：我保證從 URL 輸入的名稱是正確的。