當用戶嘗試上傳不是圖像的文件時，我試圖顯示來自 REST API 的錯誤消息。從 API 返回的 JSON 類似于：{     "publicError": "Could not be uploaded, it is not an image!",     "innerError": "WrongImageTypeException()"     }但我不知道它如何向用戶顯示。我試過了this.setState({ errorMesage: { ...err } })控制臺日志看起來像這樣https://cdn1.imggmi.com/uploads/2019/4/4/f642ed4326147b3f2c6899e78d415771-full.png。如何顯示此響應錯誤消息？后端代碼public ResponseEntity<?> uploadFile(    @RequestHeader(value = "Authorization") String authorizationHeader,    @RequestParam("file") MultipartFile file) throws UserNotFoundException {        try {            if(!(fileStorageService.checkFileType(file))){                throw new WrongImageTypeException();            }        }catch (WrongImageTypeException error){            return ResponseEntity.status(403).body(new ErrorMessageManager(                "Could not be uploaded, it is not an image!",error.toString()));        }前端代碼this.state : {      errorMesage: {        publicError: "",      }, } public uploadHandler() {    const formdata: FormData = new FormData();    formdata.set('file', this.state.avatar);    const config = {      headers: {        'Content-Type': 'multipart/form-data',        'Authorization': `Bearer ${cookies.get('tk879n')}`      }    };    axios.post(      `${serverUrl}/uploadFile`,      formdata,      config    ).then(response => {      this.setState({        userProfile: {          ...this.state.userProfile,          avatarUrl: response.data,        }      });    }    ).catch((err) => {      // i want to set error message state and display in render function      this.setState({ errorMesage: { ...err } });       console.debug(this.state.errorMesage);    });  }爪哇島反應打字腳本彈簧靴