Why is sending empty data to the server?

I have 5 text fields and a button that sends the entered data in a form understandable to the server. The problem is that the data on the server is empty. I do not understand where they went? When you click on the button, execute () occurs; This AsyncTask -

private class AddG extends AsyncTask<Void, Void, Void> { HttpURLConnection conn; BufferedWriter writer; BufferedReader reader; OutputStream output; InputStream input; String data; protected Void doInBackground(Void... params) { try { //Берём данные name_data = name_edit.getText().toString(); login_data = login_edit.getText().toString(); password_data = password_edit.getText().toString(); info_data = info_edit.getText().toString(); adress_data = adress_edit.getText().toString(); //строим отправительные данные String post_url = server_name + "/access/index.php?add"; data = "name=" + name_data + "&adress=" + adress_data + "&password=" + password_data + "&login=" + login_data + "&info=" + info_data; //пичкаем коннект URL url = new URL(post_url); conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("POST"); conn.setRequestProperty("User-Agent", "Mozilla/5.0 (compatible)"); conn.setRequestProperty("content-type","application/json; charset=utf-8"); conn.setRequestProperty("content-type","application/x-www-form-urlencoded"); conn.setRequestProperty("content-type","application/form-data"); conn.setRequestProperty("Accept","*/*"); conn.setConnectTimeout(8000); conn.setReadTimeout(8000); conn.setDoInput(true); conn.setDoOutput(true); conn.setUseCaches(false); //создаём туннель к серверу и отправляем данные output = conn.getOutputStream(); writer = new BufferedWriter(new OutputStreamWriter(output, "UTF-8")); writer.write(data); writer.flush(); writer.close(); output.close(); conn.connect(); //открываем туннель для ответа от сервера и пихаем его в result input = conn.getInputStream(); reader = new BufferedReader(new InputStreamReader(input, "UTF-8")); StringBuilder result = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { result.append(line); } } catch (Exception e) { } return null; } }