500错误服务器无法识别我的hashmap

Question

这是我的代码，为什么在发送Multipart请求后服务器仍然看到我的代码如字符串而不是hashmap？

String token2= mPreferences.getString("auth_token","");

                // open a URL connection to the Servlet
                fileInputStream = new FileInputStream(sourceFile);
                URL url = new URL(upLoadServerUri);

                //create json object
                try {
                    spot.put("title", "titolo1");
                    spot.put("latitude", "1");
                    spot.put("longitude", "1");
                    spot.put("address", "antani");
                    spot.put("country", "IT");
                    spot.put("shot_level", "pro");
                    spot.put("photo_attributes",photo_attributes);
                        photo_attributes.put("0",attributes);
                            attributes.put("description","Nesciunt dignissimos qui non. Beatae optio eveniet quis..");
                            attributes.put("our_policies","1");


                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }


                //Convert json to hashmap
                HashMap<String, String> attributesmap = new HashMap<String, String>();
                JSONObject attributesObject = new JSONObject(attributes.toString());

                HashMap<String, String> photo_attributesmap = new HashMap<String, String>();
                JSONObject photo_attributesObject = new JSONObject(photo_attributes.toString());

                HashMap<String, String> map = new HashMap<String, String>();
                JSONObject spotjObject = new JSONObject(spot.toString());


                Iterator<?> keys = spotjObject.keys();
                Iterator<?> keys2 = photo_attributesObject.keys();
                Iterator<?> keys3 = attributesObject.keys();

                while( keys3.hasNext() ){
                    String key3 = (String)keys3.next();
                    String value3 = attributesObject.getString(key3);
                    attributesmap.put(key3, value3);
                }
                while( keys2.hasNext() ){
                    String key2 = (String)keys2.next();
                    String value2 = photo_attributesObject.getString(key2);
                    photo_attributesmap.put(key2, value2);
                }
                while( keys.hasNext() ){
                    String key = (String)keys.next();
                    String value = spotjObject.getString(key);
                    map.put(key, value);
                }



                File file = new File(sglimagepath);
                try {
                    client = new DefaultHttpClient();
                    String postURL = upLoadServerUri;
                    post = new HttpPost(postURL);

                    MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);

                    ContentBody con =new StringBody(map.toString());

                    reqEntity.addPart("spot", con );

                    post.setHeader("x-auth-token", token2);
                    post.setEntity(reqEntity);
                    HttpResponse response2 = client.execute(post);
                    HttpEntity resEntity = response2.getEntity();
                    if (resEntity != null) {
                        Log.i("RESPONSE", EntityUtils.toString(resEntity));
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }

这是错误：

Invalid parameter 'spot' value 
"{address=antani, latitude=1, 
shot_level=pro, country=IT, 
title=titolo1, 
photo_attributes={\"0\":{\"description\":\
"Nesciunt dignissimos qui non. Beatae optio eveniet quis..\",
\"our_policies\":\"1\"}}, longitude=1}": Must be a Hash)

这就是服务器想要的：

Parameters: {"spot"=> {"address"=>"87 The Dr London W3 6AG, UK", "country"=>"United Kingdom", "description"=>"Descrizione prova panorama", "event_type"=>"undisclosed", "latitude"=>"51.51636627452077", "longitude"=>"-0.2641945821234576", "needs_flash"=>"false", "needs_tripod"=>"false", "shot_level"=>"easy", "things_to_avoid"=>"", "things_to_watch"=>"", "title"=>"View panorama", "photos_attributes"=>{"0"=>{"ref"=>#<ActionDispatch::Http::UploadedFile:0x007fb685cb1680 @original_filename="photo0.jpeg", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"spot[photos_attributes][0][ref]\"; filename=\"photo0.jpeg\"\r\nContent-Type: image/jpeg\r\n", @tempfile=#<Tempfile:/tmp/RackMultipart20151010-325-1qd3fl1>>}}}}

服务器想要的基本上是photo_attributes不像String，而是像HashMap。我试着去做但没什么...... 在此先感谢你们