Using HTTP Post between 2 Java servlets
===

I have setup a java servlet which accepts parameters from the URL and have it working properly:

    public class GetThem extends HttpServlet {
	
    public void doGet(HttpServletRequest request, HttpServletResponse response)
       throws IOException, ServletException
    {
		try {

				double lat=Double.parseDouble(request.getParameter("lat"));
				double lon=Double.parseDouble(request.getParameter("lon"));
				response.setContentType("text/html");
				PrintWriter out = response.getWriter();
				out.println(lat + " and " + lon);
				
			} catch (Exception e) {

				e.printStackTrace();
		}
      }       
    }

So visiting this link:
http://www.example.com:8080/HttpPost/HttpPost?lat=1&lon=2 would output: 


      "1.0 and 2.0"

I'm currently calling it from another java program using this code:

    try{
	        	URL objectGet = new URL("http://www.example.com:8080/HttpPost/HttpPost?lat=" + Double.toString(dg.getLatDouble()) + "&lon=" + Double.toString(dg.getLonDouble()));
	    	 	URLConnection yc = objectGet.openConnection();
	    	 	BufferedReader in = new BufferedReader(
			    		new InputStreamReader(
			    		yc.getInputStream()));
	    	 	in = new BufferedReader(
	    		new InputStreamReader(
	    		yc.getInputStream()));
				...


Now I want to change it so that I'm not using the URL parameters to pass this data to the server.  I want to send much larger messages to this server.  I am aware that I need to use http post rather than http get to achieve this but am not sure how to do it.

Do I need to change anything on the server side which is receiving data?  What do I need to do on the client side which is posting this data?

Any help would be greatly appreciate thanks.
Ideally I'd like to send this data in JSON format.  