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  • Servlet 实现网页计数器

    创建CounterSerlet, 使用getServletContext,ServletContext 从request.getSession().getServletContext();获得

    @WebServlet("/CounterServlet")
    public class CounterServlet extends HttpServlet {
    	private static final long serialVersionUID = 1L;
           
        /**
         * @see HttpServlet#HttpServlet()
         */
        public CounterServlet() {
            super();
            // TODO Auto-generated constructor stub
        }
    
    	/**
    	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    			ServletContext context = request.getSession().getServletContext();
    		if(null == context.getAttribute("counter")){
    			context.setAttribute("counter", 1);
    		}else {
    			int count = (Integer)context.getAttribute("counter");
    			context.setAttribute("counter", count + 1);
    		}
    		request.getRequestDispatcher("counter.jsp").forward(request, response);
    	}
    
    	/**
    	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    	 */
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		// TODO Auto-generated method stub
    		doGet(request, response);
    	}
    
    }
    

      

    2. counter.jsp

    jsp里对应的对象就是application

    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
     <%= application.getAttribute("counter") %>
    </body>
    </html>
    

      

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  • 原文地址:https://www.cnblogs.com/linlf03/p/7689807.html
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