File Upload Vulnerability

@Autowired
private StandardServletMultipartResolver standardServletMultipartResolver;

@PostMapping({"/upload/file"})
@ResponseBody
public Result upload(HttpServletRequest httpServletRequest, @RequestParam("file") MultipartFile file) throws URISyntaxException, IOException {
    String fileName = file.getOriginalFilename();
    BufferedImage bufferedImage = ImageIO.read(file.getInputStream());
    if (bufferedImage == null) {
        return ResultGenerator.genFailResult("请上传图片类型的文件");
    }
    String suffixName = fileName.substring(fileName.lastIndexOf("."));
    //生成文件名称通用方法
    SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
    Random r = new Random();
    StringBuilder tempName = new StringBuilder();
    tempName.append(sdf.format(new Date())).append(r.nextInt(100)).append(suffixName);
    String newFileName = tempName.toString();
    File fileDirectory = new File(Constants.FILE_UPLOAD_DIC);
    //创建文件
    File destFile = new File(Constants.FILE_UPLOAD_DIC + newFileName);
    try {
        if (!fileDirectory.exists()) {
            if (!fileDirectory.mkdir()) {
                throw new IOException("文件夹创建失败,路径为：" + fileDirectory);
            }
        }
        file.transferTo(destFile);
        Result resultSuccess = ResultGenerator.genSuccessResult();
        resultSuccess.setData(NewBeeMallUtils.getHost(new URI(httpServletRequest.getRequestURL() + "")) + "/upload/" + newFileName);
        return resultSuccess;
    } catch (IOException e) {
        e.printStackTrace();
        return ResultGenerator.genFailResult("文件上传失败");
    }
}`