1.  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    2.         resp.setContentType("text/html;charset=utf-8");
    3.         PrintWriter out = resp.getWriter();
    4.         ServletContext context = this.getServletContext();
    5.         Integer i =(Integer) context.getAttribute("time");
    6.         if(i==null){
    7.             i=new Integer(1);
    8.         }else{
    9.             i=new Integer(i.intValue()+1);
    10.         }
    11.         String num=context.getInitParameter("nov");
    12.         out.println("<h1>"+num+i.intValue()+"</h1>");
    13.         context.setAttribute("time",i);
    14.     }

    注意！context.setAttribute(String str,Object obj);中后面一定要是对象才能成功，否则报错，也就是说要保存数值的话必须用该类型的包装类才行。例子：
    int型的数据必须用Integer包装类才能成功保存。