testsession.java~53~

梅花雪树的经典制作

package com.test;

import javax.servlet.http.*;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.ServletContext;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2008</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class TestSession extends HttpServlet {
    public TestSession() {
    }

    public void doPost(HttpServletRequest req,
                       HttpServletResponse resp) throws ServletException,
            IOException {
        //测试session的原理
        /*
                 req.setCharacterEncoding("GBK");
                 resp.setCharacterEncoding("GBK");
                 PrintWriter out = resp.getWriter();

                 HttpSession session = req.getSession();
                 String username = (String)(session.getAttribute("username"));
                 String password = (String)(session.getAttribute("password"));

                 if(username==null&&password==null){
            session.setAttribute("username","test");
            session.setAttribute("password","test");
                 }else{
            out.print("从session里面获取的username:"+username);
            out.print("从session里面获取的password:"+password);
                 }

                 out.print("session id:"+session.getId()+"<br>");
         out.print("session CreationTime:"+session.getCreationTime()+"<br>");
                 out.print("session isNew:"+session.isNew()+"<br>");
         out.print("session LastAccessedTime:"+session.getLastAccessedTime()+"<br>");
         out.print("session RequestedSessionId:"+req.getRequestedSessionId()+"<br>");
                 out.print("session isRequestedSessionIdFromCookie:"+req.isRequestedSessionIdFromCookie()+"<br>");
                 out.print("session RequestedSessionIdFromURL:"+req.isRequestedSessionIdFromURL()+"<br>");
         out.print("<a href=\""+req.getRequestURI()+"\">连接</a>"+"<br>");
                 out.print("<a href=\""+resp.encodeURL(req.getRequestURI())+"\">连接</a>"+"<br>");*/

        //利用session实现人数统计的
        /*req.setCharacterEncoding("GBK");
                 resp.setCharacterEncoding("GBK");
                 PrintWriter out = resp.getWriter();

                 HttpSession session = req.getSession();

                 String msg = (String)(session.getAttribute("msg"));

                 FileReader fr = new FileReader("d:/count.txt");
                 BufferedReader br = new BufferedReader(fr);
                 String sNum = br.readLine();


                 if(msg==null){
                 FileWriter fw = new FileWriter("d:/count.txt");
                 BufferedWriter bw = new BufferedWriter(fw);

            int num = Integer.parseInt(sNum) + 1;
            out.print("当前在线人数是："+num);
            bw.write(String.valueOf(num));
            bw.flush();
            bw.close();
            fw.close();
            br.close();
            fr.close();
            session.setAttribute("msg","first");
                 }else{
            out.print("当前在线人数是："+sNum);
            br.close();
            fr.close();

                 }*/

        req.setCharacterEncoding("GBK");
        resp.setCharacterEncoding("GBK");
        PrintWriter out = resp.getWriter();

        HttpSession session = req.getSession();

        ServletContext sc = this.getServletContext();

        int num1 = 0;
        int num2 = 0;
        if(session.getAttribute("num1")==null){
           session.setAttribute("num1",1);
        }else{
            num1 = (Integer)(session.getAttribute("num1"));
            session.setAttribute("num1",num1+1);
        }
        out.print("session里面num1:"+session.getAttribute("num1")+"<br>");

        if(sc.getAttribute("num2")==null){
           sc.setAttribute("num2",1);
        }else{
            num2 = Integer.parseInt((String)(sc.getAttribute("num2")));
            sc.setAttribute("num2",num2+1);
        }
        out.print("ServletContext里面num2:"+sc.getAttribute("num2")+"<br>");


    }

    public void doGet(HttpServletRequest req,
                      HttpServletResponse resp) throws ServletException,
            IOException {
        this.doPost(req, resp);
    }

}