How does a JSP page send data to a servlet?

Question

I know, elementary school question, but I can't seem to do it no matter what I tried to do. Here is my code:
       URL url = new URL("http://" + ChatGlobals.SERVER_NAME + "/" +
                ChatGlobals.SERVLET_PATH + "/ppowell.ChatServlet?message=" +
                URLEncoder.encode("/a " + cookieArray.getValue())
out.println("<P>" + url.toString());
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setDoInput(true);     // NOT REALLY INTERESTED IN INPUT BUT MUST BE TRUE
conn.setDoOutput(false);     // NO OUTPUT
conn.setUseCaches(false);
conn.setDefaultUseCaches(false);
conn.setRequestProperty("Content-type", "text/plain");
     * Do servlet connection to retrieve from ChatServlet URL instance
     * by instantiating an InputStreamReader object
     * @see ChatServlet
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String stuff = null;
stuff = in.readLine();
out.print(stuff);
in.close();
in = null;
conn = null;
Upon running this code my page just locks up.. URL: http://www.myjavaserver.com/~ppowell/chat.jsp
But if I call the servlet directly:
http://www.myjavaserver.com/servlet/ppowell.ChatServlet?message=/a+Phil
Everything works perfectly, no lockups, no errors, the log and txt files are created. So if my browser calls the servlet everything is ok, but my JSP script in the same directory as my servlet is the one that needs to call the servlet.
How then does a JSP send data to a servlet?
Please help, I've been searching in books and online resources for days now with absolutely no apparent luck to do it.
Thanx
Phil

Answer 1

It's correct that a JSP is compiled to a servlet. All HTTP servlets receive requests and send responses via HTTP, of course.
But this JSP is making a URL connection to a servlet and sending data.
Are you sure that the URL your JSP creates is identical to the one that works in your browser? Have you printed it out to stdout to verify that it's true? (Code inspection and "it looks right" doesn't count.)
Why are you doing it this way? It's common to have a JSP send to a servlet, but the usual way of doing it is to put an HTML form in the JSP, including an HTML <input type="submit">, and POSTing the form data to a servlet URL. Why aren't you doing that? - MOD