Session 购物车

迈不过友情╰ 2022-04-10 13:07 313阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70][]

在jsp页面导包【Alt+/】

product\_list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    	<a href="CarServlet?id=0"><h3>Iphone7</h3></a><br>
    	<a href="CarServlet?id=1"><h3>小米6</h3></a><br>
    	<a href="CarServlet?id=2"><h3>三星Note8</h3></a><br>
    	<a href="CarServlet?id=3"><h3>魅族7</h3></a><br>
    	<a href="CarServlet?id=4"><h3>华为9</h3></a><br>
    </body>
    </html>

CarServlet.java

package com.zhujunwei;
    
    import java.io.IOException;
    import java.util.LinkedHashMap;
    import java.util.Map;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @WebServlet("/CarServlet")
    public class CarServlet 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");
    		//1、获取要添加到购物车的商品id
    		int id = Integer.parseInt(request.getParameter("id"));
    		String[] names = {"Iphone7","小米6","魅族7","华为9"};
    		String name = names[id];
    		
    		//2、获取购物车存放东西的session Map<String,Integer> Iphone7 3
    		//把一个map对象村方法到session里面去，并且保证只存放一次。
    		@SuppressWarnings("unchecked")
    		Map<String,Integer> map = (Map<String, Integer>) request.getSession().getAttribute("cart");
    		//session里面没有存放任何东西
    		if(map ==null)
    		{
    			map = new LinkedHashMap<String, Integer>();
    			request.getSession().setAttribute("cart", map);
    		}
    		//3、判断购物车里面有没有该商品
    		if(map.containsKey(name))
    		{
    			//在原来的值的基础上+1
    			map.put(name, map.get(name)+1);
    		}else {
    			//没有购买过该商品，当前数量为1
    			map.put(name, 1);
    		}
    		
    		//4.输出界面
    		response.getWriter().write("<a href='product_list.jsp'><h3>继续购物</h3></a><br>");
    		response.getWriter().write("<a href='cart.jsp'><h3>购物车结算</h3></a><br>");
    	}
    
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    
    }

Cart.jsp

<%@page import="java.util.Map"%>
    <%@ page language="java" contentType="text/html; charset=UTF-8"
        pageEncoding="UTF-8"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="UTF-8">
    <title>Insert title here</title>
    </head>
    <body>
    	<h2>您的购物车的商品如下：</h2>
    	<%
    		//1、先获取到map
    		Map<String,Integer> map = (Map<String,Integer>)session.getAttribute("cart");
    	
    		//2、遍历map
    		if(map!=null){
    			for(String key : map.keySet()){
    				int value = map.get(key);
    	%>
    				<h3>名称：<%=key %>  数量：<%=value %></h3>
    	<%
    			}
    		}
    		
    	%>
    	<a href="ClearCartServlet">清空购物车</a>
    </body>
    </html>

ClearCartServlet.java

package com.zhujunwei;
    
    import java.io.IOException;
    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;
    
    
    @WebServlet("/ClearCartServlet")
    public class ClearCartServlet extends HttpServlet {
    	private static final long serialVersionUID = 1L;
    
    	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		HttpSession session = request.getSession();
    		session.removeAttribute("cart");
    		response.sendRedirect("cart.jsp");
    	}
    
    	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    		doGet(request, response);
    	}
    
    }

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70]: /images/20220330/ca6e226fc0474a88a9ddfec915fcec55.png
[20190107144553683.gif]: /images/20220330/4fefc3ec23f9419fbdf776dec2000b63.png