HttpSession

模拟购物车页面页面

package cn.soldier.session;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/*
 * 模拟购物车页面页面
 * */
@WebServlet("/sessionDemo1")
public class SessionDemo1 extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        HttpSession session = request.getSession();
        session.setAttribute("buy", "电视机");

        /*
         * encodeUrl
         * 
         * 为url构造JSESESSIONID，防止用户禁用cookie后，session失效。
         * 第一次访问时encodeUrl会构造JSESESSIONID，
         *  当判断到用户浏览器没有禁用cookie会关闭构造JSESESSIONID
         */
        String url1 = response.encodeUrl("ServletDemo/sessionDemo1");
        String url2 = response.encodeUrl("ServletDemo/sessionDemo2");

        out.write("<a href='" + url1 + "'>购买</a></br><a href='" + url2
                + "'>结账</a>");

        // 使session失效
        /* session.invalidate(); */

    }

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);

    }
}

模拟结账页面

package cn.soldier.session;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 模拟结账页面
 */
@WebServlet("/sessionDemo2")
public class SessionDemo2 extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();

        HttpSession session = request.getSession();
        String sessionId = session.getId();
        //设置cookie 是为了防止浏览器关闭用户丢失Session。
        Cookie cookie = new Cookie("JSESESSIONID",sessionId);
        cookie.setPath("day07");
        cookie.setMaxAge(60*30);
        response.addCookie(cookie);
        
        String product = (String) session.getAttribute("buy");
        out.write("您购买了" + product+"<br />");
        
        String url1 =response.encodeUrl("ServletDemo/sessionDemo1");
        String url2 =response.encodeUrl("ServletDemo/sessionDemo2");
        
        out.write("<a href='"+url1+"'>购买</a></br><a href='"+url2+"'>结账</a>");

    }

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

    }
}