public class AjaxServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/plain"); response.setHeader("Cache-Control", "no-cache"); response.setStatus(HttpServletResponse.SC_OK); response.getWriter().write(getResponseForZip(request.getParameter("zip"))); } private String getResponseForZip(String zip) { return "97402".equals(zip) ? "Eugene,Oregon" : "NO DATA,NO DATA"; } }In our example, the Ajax servlet creates a canned response for Eugene, Oregon, only.
A real application would access a database of zip codes to find the corresponding city and state.