定义一个类 AsyncT 并在 onCreate 方法使用：

Define a class AsyncT and call it in onCreate method using:

AsyncT asyncT = new AsyncT();
asyncT.execute();

班级定义：

class AsyncT extends AsyncTask<Void,Void,Void>{

        @Override
        protected Void doInBackground(Void... params) {

            try {
                URL url = new URL(""); //Enter URL here
                HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
                httpURLConnection.setDoOutput(true);
                httpURLConnection.setRequestMethod("POST"); // here you are telling that it is a POST request, which can be changed into "PUT", "GET", "DELETE" etc.
                httpURLConnection.setRequestProperty("Content-Type", "application/json"); // here you are setting the `Content-Type` for the data you are sending which is `application/json`
                httpURLConnection.connect();

                JSONObject jsonObject = new JSONObject();
                jsonObject.put("para_1", "arg_1");

                DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
                wr.writeBytes(jsonObject.toString());
                wr.flush();
                wr.close();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }


    }