一、異常現象：

 @Override
  @PostMapping(path = "logon")
  public ResponseEntity<Boolean> logon(@RequestBody UserDTO user) {
    if (validateUser(user)) {
      UserEntity dbUser = repository.findByName(user.getName());
      if (dbUser == null) {
        UserEntity entity = new UserEntity(user.getName(), user.getPassword());
        repository.save(entity);
        return new ResponseEntity<>(true, HttpStatus.OK);
      }
      throw new InvocationException(BAD_REQUEST, "user name had exist");
    }
    throw new InvocationException(BAD_REQUEST, "incorrect user");
  }
 

二、處理
傳遞的引數格式轉換為 json 格式，http請求頭設定為 content-type : application/json;charset=UTF-8