Retrofit 2.0 上传文件

1.用MultipartBody.Part的方式上传文件（单文件上传）（表单方式）

 @Multipart
  @POST("xxx/xxx")
  Call<ResponseBody> upload(@Part MultipartBody.Part part);

其中的“photos”是与服务器端预定的文件参数名

2.用RequestBody的方式上传文件（表单方式，可多上传）

 /**
     * 多张图片上传
     */
    private void initUpateBitmap2() {

        //获取图片路径,这只是个简单的例子，项目开发中会有很多图片需要上传，一般从相册和相机里获取，并且保存到后台服务器时必须自己定义名字
        // ，这样就不会发生图片替换（原因名字重复）
        File file = new File(Environment.getExternalStorageDirectory() + "/" + "retrofit/" + "ceshi.jpg");
        File file2 = new File(Environment.getExternalStorageDirectory() + "/" + "retrofit/" + "ceshi2.jpg");
        File file3 = new File(Environment.getExternalStorageDirectory() + "/" + "retrofit/" + "ceshi3.jpg");
        File file4 = new File(Environment.getExternalStorageDirectory() + "/" + "retrofit/" + "ceshi4.jpg");

        RequestBody requestBody = RequestBody.create(MediaType.parse("multipart/form-data"), file);
        RequestBody requestBody2 = RequestBody.create(MediaType.parse("multipart/form-data"), file2);
        RequestBody requestBody3 = RequestBody.create(MediaType.parse("multipart/form-data"), file3);
        RequestBody requestBody4 = RequestBody.create(MediaType.parse("multipart/form-data"), file4);
        RequestBody body = RequestBody.create(MediaType.parse("multipart/form-data"), file);
        //传一张图片就要增加一个参数
        String name = "photo\"; filename=\"ceshi.jpg\"";
        String name2 = "photo\"; filename=\"ceshi2.jpg\"";
        String name3 = "photo\"; filename=\"ceshi3.jpg\"";
        String name4 = "photo\"; filename=\"ceshi4.jpg\"";
        HashMap<String, RequestBody> map = new HashMap<>();
        map.put(name, requestBody);
        map.put(name2, requestBody2);
        map.put(name3, requestBody3);
        map.put(name4, requestBody4);

        RetrofitHelper.getInstance().uploadFile2(map, new RetrofitHelper.OnSuccessListener() {
            @Override
            public void onSuccess(Object o) {
                Log.e("", "成功");
            }

            @Override
            public void onFaile() {
                Log.e("", "失败");

            }
        });
    }