Normaly you can GET and POST parameters in a servlet the same way:
request.getParameter("cmd");
But only if the POST data is encoded as key-value pairs of content type: "application/x-www-form-urlencoded" like when you use a standard HTML form.
If you use a different encoding schema for your post data, as in your case when you post a json data stream, you need to use a custom decoder that can process the raw datastream from:
BufferedReader reader = request.getReader();
Json post processing example (uses org.json package )
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
StringBuffer jb = new StringBuffer();
String line = null;
try {
BufferedReader reader = request.getReader();
while ((line = reader.readLine()) != null)
jb.append(line);
} catch (Exception e) { /*report an error*/ }
try {
JSONObject jsonObject = HTTP.toJSONObject(jb.toString());
} catch (JSONException e) {
// crash and burn
throw new IOException("Error parsing JSON request string");
}
// Work with the data using methods like...
// int someInt = jsonObject.getInt("intParamName");
// String someString = jsonObject.getString("stringParamName");
// JSONObject nestedObj = jsonObject.getJSONObject("nestedObjName");
// JSONArray arr = jsonObject.getJSONArray("arrayParamName");
// etc...
}