POST json data using HttpURlConnection - php

Question

I am trying to send json data to server using HTTPURLConnection. But every time response id null from server. i tried by POSter also but it is working there.
try {
jsondata ="{\"A\":\"1234\",\"country_code\":\"91\",\"name\":\"sajal\",\"phone_number\":\"88999\"}";
URL url = new URL(uri);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setConnectTimeout(3000);
httpConn.setDoInput(true);
httpConn.setDoOutput(true);
httpConn.setRequestProperty("Content-Type", "application/json;charset=UTF-8");
httpConn.setRequestMethod("POST");
StringBuffer requestParams = new StringBuffer();
if (jsondata != null && jsondata.length() > 0) {
Uri.Builder builder = new Uri.Builder().appendQueryParameter("data", jsondata);
String query = builder.build().getEncodedQuery();
OutputStream os = httpConn.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
bufferedWriter.write(query);
bufferedWriter.flush();
bufferedWriter.close();
os.close();
}
InputStream inputStream = null;
if (httpConn != null) {
inputStream = httpConn.getInputStream();
} else {
throw new IOException("Connection is not established.");
}
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
response = reader.readLine();
reader.close();
if (httpConn != null)
httpConn.disconnect();
} catch (UnknownHostException one) {
return response;
} catch (SocketException two) {
return response;
} catch (Exception three) {
return response;
}
return response;
}
Keeping my json string in "data" key
PHP:-
if (isset($_POST['data'])) {
$data = json_decode($_POST["data"], true);
// php code.....
} else {
// control comes here..
// php code.....
}
Here $_POST['data'] is not working. Please check whats wrong in PHP or Andooid code.