使用Session与Cookie实现购物流程-优快云博客

本文链接：https://blog.youkuaiyun.com/u010078400/article/details/29201559

实现一：在首页上添加“购买”、“结账”超链接，当用户点击“购买”，再点击“结账”后，在浏览器中输出用户购买的商品。

其核心“购买”Servlet为Demo1.java

package SessionDemo;

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

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

public class Demo1 extends HttpServlet
{

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException
	{
		HttpSession session = request.getSession();
		session.setAttribute("name","洗衣机");
	}

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

其核心“结账”Servlet为：Demo2.java

package SessionDemo;

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

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

public class Demo2 extends HttpServlet
{

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException
	{
		//解决中文乱码问题
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");  
		PrintWriter out = response.getWriter();  
		
		HttpSession session = request.getSession();
		String productname = (String) session.getAttribute("name");
		out.write("您购买的商品为 ： "+productname);
	}

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

其显示页面为index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
  	<title>Index.jsp</title>
  </head>
  
  <body>
    <a href="/SessionTest/servlet/Demo1">购买</a></br>
    <a href="/SessionTest/servlet/Demo2">结账</a></br>
  </body>
</html>

在浏览器中加载index.jsp

点击“购买”后，再点击“结账”，会显示

实现二：摧毁Session。

方法一：在web.xml中配置Session的失效时间，此处配置为10分钟

<session-config>
  	<session-timeout>10</session-timeout>
  </session-config>

方法二：在Servlet中加入如下代码摧毁：

//摧毁Session
session.invalidate();

实现三：在实现一中，当用户在点击“购买”后若关闭浏览器，则再次打开浏览器点击“结账”时会显示：null。利用Cookie解决此问题。

将Demo1.java改为如下

package SessionDemo;

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

import javax.servlet.ServletException;
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;

public class Demo1 extends HttpServlet
{

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException
	{
		HttpSession session = request.getSession();
		
		String sessionId = session.getId();
		//将浏览器中Session基于的Cookie覆盖
		Cookie cookie = new Cookie("JSESSIONID",sessionId);
		cookie.setPath("/SessionTest");
		cookie.setMaxAge(30*60);
		response.addCookie(cookie);
		
		session.setAttribute("name","洗衣机");
	}

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

Demo2.java不变。将首页改为index.html

<!DOCTYPE html>
<html>
  <head>
    <title>index.html</title>
	
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="this is my page">
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
    
    <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

  </head>
  
  <body>
    <a href="/SessionTest/servlet/Demo1">购买</a></br>
    <a href="/SessionTest/servlet/Demo2">结账</a></br>
  </body>
</html>

实现四：当用户浏览器设置为禁用cookie时，也可以实现“购买”、“结账”。

Demo1.java和Demo2.java不变，添加WelcomeServlet.java

package SessionDemo;

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

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

public class WelcomeServlet extends HttpServlet
{

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException
	{
		//解决中文乱码问题
		request.setCharacterEncoding("UTF-8");
		response.setContentType("text/html;charset=UTF-8");  
		PrintWriter out = response.getWriter();  
		
		request.getSession();
		String url1 = response.encodeURL("/SessionTest/servlet/Demo1");
		String url2 = response.encodeURL("/SessionTest/servlet/Demo2");
		
		out.print("<a href='"+url1+"'>购买</a></br>");
		out.print("<a href='"+url2+"'>结账</a></br>");
	}

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

在浏览器中将cookie禁用，加载WelcomeServlet.java,可看到（注意地址栏变化）