我在springboot开发一个电子商务web应用程序。我面临http状态500错误。实际上，我正试图提交一个表单，在其中我上传一个产品图片。所有功能都正常工作，但当我点击submit按钮时，出现一个内部服务器错误，消息如下：
2021-04-21 12:32:18.511 warn 20042---[nio-9111-exec-2].w.s.m.s.defaulthandlerexceptionresolver:已解析[org.springframework.web.method.annotation.methodargumentconversionnotsupportedexception:未能将类型“org.springframework.web.multipart.support.StandardMultipathTtpServletRequest$standardmultipartfile”的值转换为所需类型'java.lang.string'；嵌套异常为java.lang.illegalstateexception:无法将类型为“org.springframework.web.multipart.support.StandardMultipartAttpServletRequest$standardmultipartfile”的值转换为所需类型“java.lang.string”：找不到匹配的编辑器或转换策略]
下面是我上传文件的控制器代码。在下面的代码中，我提取了文件名及其扩展名，然后将其转换为字节。

@RequestMapping(value = ApiUrl.uploadfile, method = { RequestMethod.POST, RequestMethod.GET }, produces = {MediaType.APPLICATION_JSON_VALUE })
    public ResponseEntity<?> uploadfile(HttpServletRequest request, @RequestParam("file") MultipartFile file) {
        CustomResponse = ResponseFactory.getResponse(request);
        String imgurl = "NA";
        try {
            String path = Constants.webmedia;
            String relativepath = "public/media/";
            System.out.println("Here is the image: ");
            if (null != file) {
                String filename = file.getOriginalFilename();
                String extension = filename.substring(filename.lastIndexOf("."), filename.length());
                System.out.println("filename : " + filename + " || extension : " + extension);
                SimpleDateFormat format = new SimpleDateFormat("yyyyMMddhhmmss");
                Date date = new Date();
                String formatdate = format.format(date);
                formatdate = "imgurl" + formatdate;
                System.out.println("formatdate : " + formatdate);
                byte[] bytes = file.getBytes();
                BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(new File(path + File.separator + formatdate + extension)));
                stream.write(bytes);
                stream.flush();
                stream.close();
                imgurl = relativepath + formatdate + extension;
                System.out.println("imgurl : " + imgurl);
                if (imgurl != null) {
                    CustomResponse.setResponse(imgurl);
                    CustomResponse.setStatus(CustomStatus.OK);
                    CustomResponse.setStatusCode(CustomStatus.OK_CODE);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            CustomResponse.setResponse(null);
            CustomResponse.setStatus(CustomStatus.Error);
            CustomResponse.setStatusCode(CustomStatus.Error_CODE);
            CustomResponse.setResponseMessage(CustomStatus.ErrorMsg);
        }
        return new ResponseEntity<ResponseDao>(CustomResponse, HttpStatus.OK);
    }