自己整这个问题整了半天，写篇博客记录下
private void uploadMultiFile() {
    String imageType = "multipart/form-data";
    File file = new File(imgUrl);imgUrl为图片位置
    RequestBody fileBody = RequestBody.create(MediaType.parse("image/jpg"), file);
    RequestBody requestBody = new MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("file", "head_image", fileBody)
            .addFormDataPart("imagetype", imageType)
            .build();
    Request request = new Request.Builder()
            .url(url)
            .post(requestBody)
            .build();
    final okhttp3.OkHttpClient.Builder httpBuilder = new OkHttpClient.Builder();
    OkHttpClient okHttpClient = httpBuilder
            .build();
    okHttpClient.newCall(request).enqueue(new Callback() {
        @Override
        public void onFailure(Request request, IOException e) {

        }

        @Override
        public void onResponse(Response response) throws IOException {
            String htmlStr = response.body().string();
            Log.i("result", htmlStr);
           
        }
    });
}

Android 使用okhtth上传图片multipart/form-data