如何在改造中发布对象（包括字节数组）？

Question

我将捕获的图像转换为字节数组，并尝试将对象（包括字节数组）发布到Retrofit中的服务器上，但是没有用。这是我的代码，谢谢。

Photo_List.java

public class Photo_List {

int FileId;
byte[] Picture;
String User;

public Photo_List(int FileId, byte[] Picture, String User) {
    this.FileId=FileId;
    this.User=User;
    this.Picture=Picture;
}
public int getFileId() {
    return FileId;
}
public byte[] getPicture() {
    return Picture;
}

public String getUser() {
    return User;
}

}

-我的方法-

 private void multipartImageUpload() {

    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    mBitmap.compress(Bitmap.CompressFormat.PNG, 70, bos);
    byte[] bitmapdata = bos.toByteArray();

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl("MYURL")
            .addConverterFactory(GsonConverterFactory.create())
            .build();
    Photo_List item = new Photo_List(5, bitmapdata, "michonne");

    ApiService apiService = retrofit.create(ApiService.class);

    Call<Photo_List> photo_listCall = apiService.postImage(item);

    photo_listCall.enqueue(new Callback<Photo_List>() {
        @Override
        public void onResponse(Call<Photo_List> call, Response<Photo_List> response) {
            Log.d("GG", response.message());
            Toast.makeText(getApplicationContext(), " :) ", Toast.LENGTH_LONG).show();
        }

        @Override
        public void onFailure(Call<Photo_List> call, Throwable t) {
            Log.e("WP", t.getMessage());
            Toast.makeText(getApplicationContext(), ":(", Toast.LENGTH_LONG).show();
        }
    });}

ApiService.java

public interface ApiService {

@POST("api/r_photo")
Call<Photo_List> postImage(@Body Photo_List items);

}

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POST api /

公共HttpResponseMessage帖子（照片）