一个好玩简单的购物车

最新推荐文章于 2022-06-13 12:00:30 发布

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博客提及puduct.jsp和cart.jsp购物车的jsp，还涉及servlet，鼓励读者亲自尝试，或许能唤起相关回忆，主要围绕JSP和Servlet开发内容。

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puduct.jsp

<%@ 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>
    <a href="product?id=0"><h3>Iphone8</h3></a><br/>
    <a href="product?id=1"><h3>小米6</h3></a><br/>
    <a href="product?id=2"><h3>三星Note8</h3></a><br/>
    <a href="product?id=3"><h3>华为9</h3></a><br/>
    <a href="product?id=4"><h3>魅族6</h3></a><br/>

</body>
</html>

下面是cart.jsp购物车的jsp

<%@page import="java.util.Map"%>
<%@ 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>

    <%
        Map<String,Integer> map=(Map<String,Integer>)request.getSession().getAttribute("cart");
        if(map!=null){
            for(String key: map.keySet()){
                int value=map.get(key);
                %>
                <h2>名称：<%=key %>  数量：<%=value %></h2>
                <%
            }
        }
    %>

</body>
</html>

这里是servlet

package com.dong.servlet;

import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;

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

public class ProductServlet extends HttpServlet {
    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[] goods= {"Iphone8","小米6","三星Note8","华为9","魅族6"};

        //取到id对应的商品名称
        String name=goods[id];

        //2. 获取购物车存放东西的session  Map<String , Integer>  iphoen7 3
        Map<String,Integer> map = (Map<String, Integer>) request.getSession().getAttribute("cart");

        //把一个map对象存放到session里面去，并且保证只存一次。

        //session里面没有存放过任何东西。
        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)) {
            //有这个商品，在原来的值基础上  + 1 
            map.put(name, map.get(name)+1);
        }else {
            //没有购买，当前数量 为1
            map.put(name, 1);
        }


        //4. 输出界面。（跳转）
        response.getWriter().write("<a href='product.jsp'><h3>继续购物</h3></a>");
        response.getWriter().write("<a href='cart.jsp'><h3>回到我的购物车结算</h3></a>");

    }

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

}