Java android AsyncHttpClient 如何设置标头“Accept”“application/xml”或“application/json”

我不知道如何为“applicatjon/json”设置标头“Accept”，现在我来自服务器的响应是 xml，但我想要一个 json。当我设置标头时，服务器应该向我发送一个 xml。这是我的代码：

  final JSONObject requestObject = new JSONObject();
        try {
            requestObject.put("company", "TEST");
            requestObject.put("user", "pawelo");
            requestObject.put("secure_password", "8ce241e1ed84937ee48322b170b9b18c");
            requestObject.put("secure_device_id", "C4CA4238A0B923820DCC509A6F75849B");
        } catch (JSONException e) {
            e.printStackTrace();
        }


        StringEntity entity = null;
        try {
            entity = new StringEntity(requestObject.toString());
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
client.post(this, url, entity, "application/json",
            new  BaseJsonHttpResponseHandler("UTF-8") {

                @Override
                public void onSuccess(int statusCode, Header[] headers, String rawJsonResponse, Object response) {
                    Log.e("sdasa " , rawJsonResponse + " " + statusCode);
                }

                @Override
                public void onFailure(int statusCode, Header[] headers, Throwable throwable, String rawJsonData, Object errorResponse) {

                }

                @Override
                protected Object parseResponse(String rawJsonData, boolean isFailure) throws Throwable {
                    return null;
                }
            });

            JSONObject json = new JSONObject();

            JSONObject dataJson = new JSONObject();
            dataJson.put("body", message);
            dataJson.put("title", getFirebaseUser().getDisplayName());
            json.put("notification", dataJson);
            json.put("registration_ids",jsonArray);


            StringEntity se = new StringEntity(json.toString(), "UTF-8");

            AsyncHttpClient client = new AsyncHttpClient();
            client.addHeader("Accept", "application/json");
            client.addHeader("Content-type", "application/json;charset=utf-8");
            client.addHeader("Authorization", "key=" + "xxxxxxxxxxxx");
            client.post(getInstance(), "your url", se, "application/json;charset=utf-8", new AsyncHttpResponseHandler() {
                @Override
                public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                    Log.e("success_noti", new String(responseBody) + "");

                    if(isEnd){
                        getMessage.getMessageFunc(END);
                    }

                }

                @Override
                public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
                    Log.e("fail_noti", new String(responseBody) + "");
                }
            });

使用AsyncHttpClient Library 这也是另一种方法。