AJAXserver

public class AJAXServer extends HttpServlet {

    /** 
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=utf8");
        PrintWriter out = response.getWriter();
        try {
            String old = request.getParameter("name");
            if(old == null){
                out.println("用户名不能为空");
            }
            else{
                String name = new String(old.getBytes("ISO8859-1"),"gb2312");
                System.out.println(name);
                
                if(name.equals("test")){
                    out.println("用户名（"+name+"）已经存在请用其他名字");
                }
                else{
                    out.println("用户名（"+name+"）未使用，可以建立");
                }
            }
        }catch(Exception e){
            
            out.println("致命错误"+e.toString());
            
        }
        finally {
            out.close();
        }
    }