flutter 上传图片 我是按照dio官方的代码写的 但是服务器接收不到

flutter 上传图片 我是按照dio官方的代码写的 但是服务器接收不到,真是够够的~~~
我们两个用了很多种办法 测试 搞了一天半 终于搞出来了
老规矩 废话不多说 直接上代码

flutter 代码

上传代码

 HttpHelper httpHelper = new HttpHelper();
    httpHelper.controller = value.changeAvatarC;
    httpHelper.action = value.changeAvatarA;
    String path = imageFile.path;
    var name = path.substring(path.lastIndexOf("/") + 1, path.length);
    var suffix = name.substring(name.lastIndexOf(".") + 1, name.length);
    FormData formData = FormData.from({
      "username":widget.model.username,
      "file":new UploadFileInfo(new File(path), name,contentType: ContentType.parse("image/$suffix")),
    });
    httpHelper.post(data: formData).then((m){
      func();
      if(m == 3){
        Fluttertoast.showToast(msg: "修改成功");
        Navigator.pop(context);
      }
    });

httphelper 里面的post代码

 /*
   * post请求
   */
  Future post({data, Options options, cancelToken}) async {
    Response response;
    if(data == null){
      data = new FormData();
    }
    String url = builder();
    data[value.login_token] = await Tool().getString(value.token);
    print("post url =====================$url          params =============== $data");
    print("options  ===================== $options");
    try {
      response = await dio.post(url, data: data, options: options, cancelToken: cancelToken);
      print('post success---------${response.data}');
    } on DioError catch (e) {
      print('post error---------$e');
        formatError(e);
      return null;
    }
    return response.data;
  }

java代码(我的后台是java)

Part part = request.getPart("file");
String fileNames = getFileName(part);
String path = writeTo(fileNames,part,nowDate);

private String getFileName(Part part) {
  String head = part.getHeader("Content-Disposition");
  String fileName = head.substring(head.indexOf("filename=\"")+10, head.lastIndexOf("\""));
  System.out.println(fileName);
  return fileName;
}
private String writeTo(String fileName, Part part,String nowDate)throws IOException {
  String addAndFilename = "/"+"upload" + "/" + nowDate + "/";
  filesPath=filesPath.replace("file:","");
  String finalPath = filesPath + addAndFilename;
  if (!new File(finalPath).exists() || !new File(finalPath).isDirectory()) {
    new File(finalPath).mkdirs();
  }
  InputStream in = part.getInputStream();
  OutputStream out = new FileOutputStream(finalPath+fileName);
  byte[] b = new byte[1024];
  int length = -1;
    while((length = in.read(b))!=-1){
    out.write(b, 0, length);
  }
  in.close();
  out.close();
  return finalPath+fileName;
}

他告诉我这是个非常冷门的东西 基本上很少用 如果大胸弟们需要其他的代码 评论区找我 我知无不言言无不尽