HttpServletRequest JSON parameter found null value in Servlet

Question

I'm using Servlet to handle request and response.

I have used following code to Servlet my request to sublet using webservice:

 JSONObject parans = new JSONObject();
    parans.put("commandid", "Enamu7l");
    System.out.println("parans = " + parans);        
    Client restClient = Client.create();
    WebResource webResource = restClient.resource("URL");
    ClientResponse resp = webResource.accept(MediaType.APPLICATION_JSON)
            .post(ClientResponse.class, parans.toJSONString());

Here is my servlet code to receive data.

 @Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    String commandid= request.getParameter("commandid");        
    System.out.println(commandid);       
}

commandid recieve null from webservice.

What to do in webservice to get data in servlet?

Answer 1

WebResource not sending the data as part of the url, so you can not use request.getParameter . The data is send as request body using the post method.Read the data using the reader.

       StringBuilder sb = new StringBuilder();
        while ((s = request.getReader().readLine()) != null) {
            sb.append(s);
        }
       JSONObject jSONObject = new JSONObject(sb.toString());

        System.out.println(jSONObject.getString("commandid"));

Answer 2

You are sending JSON in request body , so you need to get it:

String json = request.getReader().lines().collect(Collectors.joining());

Convert to JSON:

JSONObject jsonObject = new JSONObject(json);

And get the value:

String value = jsonObject.getString("commandid");