通过Servlet实现计算器

来源：互联网发布：女装尺码表参照数据编辑：程序博客网时间：2024/05/16 09:43

package com.milk.servlet;

import java.io.IOException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ConterServlet extends HttpServlet
{
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp)
           throws ServletException, IOException
   {
       ServletContext context = req.getSession().getServletContext();

       if(null == context.getAttribute("counter"))
       {
           context.setAttribute("counter", 1);
       }
       else
       {
           int num = (Integer)(context.getAttribute("counter"));
           context.setAttribute("counter", num+1);
       }

       req.getRequestDispatcher("counter.jsp").forward(req, resp);
   }

}

jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'counter.jsp' starting page</title>

   <meta http-equiv="pragma" content="no-cache">
   <meta http-equiv="cache-control" content="no-cache">
   <meta http-equiv="expires" content="0">
   <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
   <meta http-equiv="description" content="This is my page">

</head>

<body>
    计数器: <%= application.getAttribute("counter") %>>
</body>
</html>