改造OkHttp HttpLoggingInterceptor显示正确响应，但是改造显示不正确响应

Question

我正在尝试将照片上传到服务器。 我的问题是我无法链接到服务器返回给我的这张图片。

public class RetrofitClient {

    public static Retrofit createService(
            String username, String password) {
        String authToken = Credentials.basic(username, password);
        return createService(authToken);
    }

    public static Retrofit createService(final String authToken) {
        AuthenticationInterceptor interceptor = null;
        if (!TextUtils.isEmpty(authToken))
            interceptor =    new AuthenticationInterceptor(authToken);




        Gson gson = new GsonBuilder()
                .setLenient()
                .create();
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        final OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .addInterceptor(logging)
                .retryOnConnectionFailure(true)
                .readTimeout(30, TimeUnit.SECONDS)
                .connectTimeout(30, TimeUnit.SECONDS).build();

        return new Retrofit.Builder()
                .baseUrl(AppConstant.BASE_URL+"/")
                .client(client)
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .addConverterFactory(GsonConverterFactory.create(gson))
                .addConverterFactory(ScalarsConverterFactory.create())
                .build();


    }

    public static RetroInterface getApiServices(String user_name, String passowrd) {
        return createService(user_name, passowrd).create(RetroInterface.class);
    }
}

RetroInterface.java

....
@Multipart
@POST("parents/profile/images")
Call<String>
uploadParentProfilePicture2(@Part MultipartBody.Part filePart);
....

Profile.java

....
MultipartBody.Part filePart = MultipartBody.Part.createFormData("file", file.getName(), RequestBody.create(MediaType.parse("image/*"), file));
        RetroInterface retroInterface = RetrofitClient.getApiServices(getEmail(), getPassword());
        Call<String> call = retroInterface.uploadParentProfilePicture(filePart);
        call.enqueue(new Callback<String>() {
            @Override
            public void onResponse(@NonNull Call<String> call, @NonNull Response<String> response) {
                    Log.d("ldsfjjlk", "response: " + response.body());
            }

            @Override
            public void onFailure(@NonNull Call<String> call, @NonNull Throwable t) {
                Log.d("ldsfjjlk", "Throwable: " + t.getLocalizedMessage());
            }
        });
....

HttpLoggingInterceptor响应：

"parents/654/profile/images/1530979485020.jpg" 

是的！

我的日志：

"parents"

这是什么？

翻新有问题吗？

我也尝试替换 Call<String>至Call<ResponseBody>，但： response.body.string() == null 我想念什么？