Java 在角形弹簧启动中上载图像时没有类似的错误

我将在angular和spring boot中保存一个图像，并得到一个“NoTouchElementException”错误。 我的上传服务

filesToUpload: Array<File>;

  constructor() {
    this.filesToUpload = [];
  }

  upload(bookId: number) {
    this.makeFileRequest("http://myurl/add/image?id="+dataId, [], this.filesToUpload).then((result) => {
        console.log(result);
    }, (error) => {
        console.log(error);
    });
  }

  fileChangeEvent(fileInput: any) {
    this.filesToUpload = <Array<File>> fileInput.target.files;
  }

  makeFileRequest(url:string, params:Array<string>, files:Array<File>) {
    return new Promise((resolve, reject) => {
        var formData:any = new FormData();
        var xhr = new XMLHttpRequest();
        for(var i=0; i<files.length;i++) {
            formData.append("uploads[]", files[i], files[i].name);
        }
        xhr.onreadystatechange = function() {
            if(xhr.readyState == 4) {
                if(xhr.status==200) {
                    console.log("image uploaded successfully!");
                } else {
                    reject(xhr.response);
                }
            }
        }

        xhr.open("POST", url, true);
        xhr.setRequestHeader("x-auth-token", localStorage.getItem("xAuthToken"));
        xhr.send(formData);
    });
  }

我的上传控制器

@RequestMapping(value = "/add/image", method = RequestMethod.POST)
    public ResponseEntity upload(@RequestParam("id") Long id, HttpServletResponse response,
            HttpServletRequest request) {
        try {
            Book book = bookService.findOne(id);
            MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
            Iterator<String> it = multipartRequest.getFileNames(); //my error is here, I got an empty iterator
            MultipartFile multipartFile = multipartRequest.getFile(it.next());
            String fileName = id + ".jpg";

            byte[] bytes = multipartFile.getBytes();
            BufferedOutputStream stream = new BufferedOutputStream(
                    new FileOutputStream(new File("src/main/resources/static/image/book/" + fileName)));
            stream.write(bytes);
            stream.close();

            return new ResponseEntity("Upload Success!", HttpStatus.OK);
        } catch (Exception e) {
            e.printStackTrace();
            return new ResponseEntity("Upload failed!", HttpStatus.BAD_REQUEST);
        }
    }

@RequestMapping（value=“/add/image”，method=RequestMethod.POST）
公共响应性上载（@RequestParam（“id”）长id，HttpServletResponse，
HttpServletRequest（请求）{
试一试{
Book Book=bookService.findOne（id）；
MultipartTTpServletRequest multipartRequest=（MultipartTTpServletRequest）请求；
迭代器it=multipartRequest.getFileNames（）；//我的错误在这里，我得到了一个空迭代器
MultipartFile MultipartFile=multipartRequest.getFile（it.next（））；
字符串文件名=id+“.jpg”；
byte[]bytes=multipartFile.getBytes（）；
BufferedOutputStream=新的BufferedOutputStream(
新文件输出流（新文件（“src/main/resources/static/image/book/”+fileName））；
stream.write（字节）；
stream.close（）；
返回新的响应属性（“上传成功！”，HttpStatus.OK）；
}捕获（例外e）{
e、 printStackTrace（）；
返回新的响应属性（“上载失败！”，HttpStatus.BAD_请求）；
}
}

我在java.util.LinkedHashMap$LinkedHashInterator.nextNode（LinkedHashMap.java:721）处发现了这个错误 我验证了代码debbug，并在数据库中获得了元素，但当我使用MultipartFile MultipartFile=multipartRequest.getFile（it.next（））时，迭代器中的元素为空

@RequestMapping(value = "/add/image", method = RequestMethod.POST)
    public ResponseEntity upload(@RequestParam("id") Long id, HttpServletResponse response,
            HttpServletRequest request) {
        try {
            Book book = bookService.findOne(id);
            MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
            Iterator<String> it = multipartRequest.getFileNames(); //my error is here, I got an empty iterator
            MultipartFile multipartFile = multipartRequest.getFile(it.next());
            String fileName = id + ".jpg";

            byte[] bytes = multipartFile.getBytes();
            BufferedOutputStream stream = new BufferedOutputStream(
                    new FileOutputStream(new File("src/main/resources/static/image/book/" + fileName)));
            stream.write(bytes);
            stream.close();

            return new ResponseEntity("Upload Success!", HttpStatus.OK);
        } catch (Exception e) {
            e.printStackTrace();
            return new ResponseEntity("Upload failed!", HttpStatus.BAD_REQUEST);
        }
    }