本篇文章讲的是如何使用javaweb相关知识模拟购物车功能

(web练手小项目)

使用到的相关知识(部分知识点在文章中简单涉及到):

       html  cs  javascript  jsp  servlet   ajax  jQuery  Mysql  MyBatis(持久层框架，用来连接数据库，这里可以使用jdbc进行数据库的连接)  功能使用MVC设计模式，以及三层架构思想

注: 本篇使用Session对购物车进行存储,具体参考下文WelcomeServlet.java

功能实现效果:

6fa64acb07db475a83fa7976e87c7527.png

5b166471e3a040da89a271db28a1af3f.png

044cb41da4ad4b4aa0b1dee10b6aa778.png

5e0d1203d22744939a4229b7fd4d55c1.png

49277781ce544930bb5600f26594b7ac.png

购物车为空状态 

6629d9457ce4476b9dc42fb3d912b696.png

 功能大致目录结构:
863ced0c16cb4953a79157a993bfc207.png

06acba73a1d042358926f78a1fa1ffb3.png

 

前端界面代码:

 (1) shopcar.jsp(购物车界面)

<%@ page import="edu.pdsu.shop.pojo.CarGoods" %>
<%@ page import="java.util.List" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>shop car</title>
    <link rel="stylesheet" href="css/shoplist.css" type="text/css">
    <script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-3.6.1.min.js"></script>
</head>
<style type="text/css">
    th, td {
        border-bottom: 1px solid green;
    }
    th {
        background-color: #4CAF50;
        color: white;
    }
    table{
        text-align: center;
    }
</style>
<body style="background-color: #ffffe0" background="img/11.webp">
<h1 style="color: white;margin-left: 600px;margin-top: 50px">购物车</h1>
<table border="1px" cellspacing="0" style="border-color: #d7ffff ; margin-top: 5px ; margin-left: 340px">
    <script type="text/javascript">
        function judgeDelete(carGoodsName) {
            if (confirm("是否删除" + carGoodsName)) {
                window.location.href = "${pageContext.request.contextPath}/deleteCarGoods?carGoodsName=" + carGoodsName
            } else {
                alert("取消删除成功")
            }
        }
    </script>

    <c:if test="${empty carGoodsList}">
        <%--<h1 style="margin-left: 580px;margin-top: 170px">购物车为空</h1>--%>
        <div style="margin-left: 500px;margin-top: 56px">
            <img src="img/carnull.jpg" width="300px" height="200px">
        </div>
    </c:if>

    <c:if test="${not empty carGoodsList}">
        <tr>
            <th>商品名称</th>
            <th>商品描述</th>
            <th>价格</th>
            <th>购买数量</th>
            <th>操作</th>
        </tr>
    </c:if>
    <c:if test="${not empty carGoodsList}">

        <c:forEach items="${carGoodsList}" var="CarGoods">
            <tr>
                <td>${CarGoods.carGoodsName}</td>
                <td>${CarGoods.carGoodsDes}</td>
                <td>${CarGoods.carGoodsPrice}</td>
                <td>${CarGoods.buyCount}</td>
                <td>
                    <input id="deleteCarGoods" type="button" style="text-decoration: none"
                           onclick="judgeDelete('${CarGoods.carGoodsName}')" value="删除"/>
                </td>
            </tr>

        </c:forEach>
    </c:if>
</table>

<c:if test="${not empty carGoodsList}">
    <h3 style="margin-left: 340px;color: white">目前您购物车的总价格为:${money}元人民币</h3>
</c:if>

<br>
<br>
<br>
<input class="backshowlist" type="button" value="返回商品显示页"
       onclick="window.location.href='${pageContext.request.contextPath}/showlist'">
</body>
</html>

 

 (2) shoplist.jsp(商品页)

<%@ page contentType="text/html;charset=utf-8" language="java" isELIgnored="false" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<head>
    <title>myshop</title>
    <link rel="stylesheet" href="css/shoplist.css" type="text/css">
    <script type="text/javascript" src="js/jquery-3.6.1.min.js"></script>
</head>
<style type="text/css">
    th, td {
        border-bottom: 1px solid green;
    }
    th {
        background-color: #4CAF50;
        color: white;
    }
    table{
        text-align: center;
    }
</style>

<body style="background-color: #ffffe0" background="img/11.webp">
<h2 style="color: skyblue">:)</h2>

<script type="text/javascript">
    $(function () {
        $("#showbtn").click(function () {
            $.ajax({
                type: "GET",
                url: "${pageContext.request.contextPath}/judgecar",
                async: true,
                success: function (j) {
                    if (j == "购物车为空") {
                        alert("购物车为空")
                    } else {
                        window.location.href = "${pageContext.request.contextPath}/shopcar.jsp"
                    }
                }
            })
        })
    })
</script>
<h1 style="color: white;margin-left: 600px">商品页</h1>
<button id="showbtn" class="showcarbtn">查看购物车</button>
<form action="${pageContext.request.contextPath}/beforeCar" method="post" id="form_">
    <table  cellspacing="0" style="  margin-top: 5px ; margin-left: 270px ;border-color: #8bff73">
        <tr>
            <th>序号</th>
            <th>商品名称</th>
            <th>商品描述</th>
            <th>商品价格(元)</th>
            <th>库存数量</th>
            <th>添至购物车</th>
        </tr>

        <c:forEach items="${goodss}" var="goods" varStatus="goodStatus">
            <tr>
                <td>${goodStatus.count}</td>
                <td>${goods.goodsName}</td>
                <td>${goods.goodsDes}</td>
                <td>${goods.goodsPrice}</td>
                <td>${goods.goodsCount}</td>
                <td>
                    <input type="checkbox" name="buy" value="${goods.goodsName}" style="margin-left: 30px">
                </td>
            </tr>
        </c:forEach>
    </table>
    <br>

    <input type="button" value="确定" id="btn" class="ensure">
    &nbsp;&nbsp;&nbsp;&nbsp;
    <input type="reset" value="重置" class="reset">

</form>

<script type="text/javascript">
    $(function () {
        $("#btn").click(function () {
            var flag = false;
            var $checkbox = $(":checkbox");
            /*for (var i = 0; i < $checkbox.length; i++) {
                if($checkbox[i].checked){
                    flag = true;
                }
            }*/
            //使用jQuery循环jQuery对象，其实jQuery对象就是一个dom数组
            /*$checkbox.each(function (i , n) {
                if(n.checked){
                    flag = true
                }
            })*/
            $.each($checkbox,function (i,n) {
                if(n.checked){
                    flag = true;
                }
            })
            if (flag == false) {
                alert("未选择商品")
            } else {
                var $formElement = $("#form_")[0];
                $formElement.submit();
            }
        })
    })
</script>
</body>
</html>

后端servlet代码:

 

欢迎页(WelcomeServlet.java)

欢迎页介绍：当把购物车初始化在ShopServlet.java或者其他servlet中刷新浏览器页面session中的购物车状态会出现异常,因此我的想法是在欢迎页中创建购物车对象并存储到Session中

写此欢迎页代码前需要在web.xml配置文件中配置一下代码

 配置后会默认以/welcome为项目默认路径进行访问(需要注意<welcome-file>这里不需要 /</welcome-file>)

<!--配置欢迎页-->
    <welcome-file-list>
        <welcome-file>welcome</welcome-file>
    </welcome-file-list>

WelcomeServlet.java 

 

package edu.pdsu.shop.servlet;

import edu.pdsu.shop.pojo.CarGoods;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

/**
 * 使用Session mybatis jsp servlet EL JSTL  AJAX JQuery模拟购物车功能的实现
 * 欢迎页(欢迎页中创建购物车对象存储到session中)
 */
@WebServlet("/welcome")
public class WelComeServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        //将购物车写到这里是为了防止进入到shoplist中用户刷新，购物车置空的情况
        //当下面的这段构建购物车的代码写到showlist->对应的servlet中，如果刷新页面，那么showlist->servlet会在次执行，重新创建List集合，购物车会置空
        List<CarGoods> carGoodsList = new ArrayList<>();
        //将购物车所有的实体商品存入Session中,
        HttpSession session = request.getSession();
        session.setAttribute("carGoodsList",carGoodsList);
        //重定向
        response.sendRedirect(request.getContextPath() + "/showlist");
    }
}

ShopServlet.java(负责获取所有商品的数据并传到前端进行数据展示)

package edu.pdsu.shop.servlet;

import edu.pdsu.shop.pojo.CarGoods;
import edu.pdsu.shop.pojo.goods;
import edu.pdsu.shop.service.ShopService;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

/**
 * 展示商品页servlet
 */
@WebServlet("/showlist")
public class ShopServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        //创建service对象
        ShopService service = new ShopService();
        //调用服务
        List<goods> goodss = service.showShopListService();
        //转发
        request.setAttribute("goodss",goodss);
        request.getRequestDispatcher("/shoplist.jsp").forward(request,response);
    }
}

BeforeCarServlet.java(在跳转到购物车界面前需要进行的操作 , 同时将数据传入前端进行展示)

package edu.pdsu.shop.servlet;

import edu.pdsu.shop.exception.UpdateErrorException;
import edu.pdsu.shop.pojo.CarGoods;
import edu.pdsu.shop.pojo.goods;
import edu.pdsu.shop.service.ShopService;
import edu.pdsu.shop.util.SqlSessionUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import org.apache.ibatis.session.SqlSession;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * 在展示购物车(shopcar.jsp)之前需要进行判断
 *      如果购物车中包含某类商品，则此类商品购买数量加一
 *      否则购物车中新增此商品的记录
 */
@WebServlet("/beforeCar")
public class BeforeCarServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request,response);
    }

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

        //创建service方法
        ShopService service = new ShopService();
        //拿到前端传来的数据
        String[] buys = request.getParameterValues("buy");
        //获取购物车信息
        HttpSession session = request.getSession();
        List<CarGoods> carGoodsList = (List<CarGoods>) session.getAttribute("carGoodsList");
        if (buys != null ) {
            boolean flag = false;
            for (String buy : buys) {
                if (carGoodsList.isEmpty()) {
                    goods goods = service.selectByGoodsNameService(buy);
                    CarGoods carGoods2 = new CarGoods();
                    carGoods2.setCarGoodsName(goods.getGoodsName());
                    carGoods2.setCarGoodsDes(goods.getGoodsDes());
                    carGoods2.setBuyCount(1);
                    try {
                        //更新商品库存服务
                        service.updateGoodsCountservice(buy);
                        //设置购物车中商品的价格
                        carGoods2.setCarGoodsPrice(goods.getGoodsPrice());
                        carGoodsList.add(carGoods2);


                    } catch (UpdateErrorException e) {
                        out.print(e.getMessage());
                    }
                } else {
                    for (int i = 0; i < carGoodsList.size(); i++) {
                        if (carGoodsList.get(i).getCarGoodsName().equals(buy)) {
                            //购物车中有用户想要购买的商品,将购物车中的商品数量加1
                            carGoodsList.get(i).setBuyCount(carGoodsList.get(i).getBuyCount() + 1);
                            //更新商品的库存
                            try {
                                service.updateGoodsCountservice(buy);
                            } catch (UpdateErrorException e) {
                                e.printStackTrace();
                            }
                            flag = true;
                        }
                    }
                    if (flag == false) {
                        //购物车中没有此商品，将购物车中加入此商品
                        goods goods = service.selectByGoodsNameService(buy);
                        CarGoods carGoods = new CarGoods();
                        carGoods.setCarGoodsName(goods.getGoodsName());
                        carGoods.setCarGoodsDes(goods.getGoodsDes());
                        carGoods.setBuyCount(1);
                        try {
                            //更新数据库中的数据信息
                            service.updateGoodsCountservice(buy);

                            carGoods.setCarGoodsPrice(goods.getGoodsPrice());
                            carGoodsList.add(carGoods);
                        } catch (UpdateErrorException e) {
                            e.printStackTrace();
                        }


                    }
                    //重新设置flag的值为false
                    flag = false;

                }
            }
            //更新购物车的信息
            double money = 0;
            for (int i = 0; i < carGoodsList.size(); i++) {
                double carGoodsPrice = carGoodsList.get(i).getCarGoodsPrice();
                int buyCount = carGoodsList.get(i).getBuyCount();
                money += carGoodsPrice * buyCount;
            }
            HttpSession session1 = request.getSession();
            session1.setAttribute("money", money);
            request.setAttribute("carGoodsList", carGoodsList);
            //转发到购物车界面
            request.getRequestDispatcher("/shopcar.jsp").forward(request, response);

        } else {
            //更新购物车的信息
            request.setAttribute("carGoodsList", carGoodsList);
            //转发到购物车界面
            request.getRequestDispatcher("/shopcar.jsp").forward(request, response);
        }

    }
}

CarServlet.java(购物车删除功能实现)

package edu.pdsu.shop.servlet;

import edu.pdsu.shop.exception.UpdateErrorException;
import edu.pdsu.shop.pojo.CarGoods;
import edu.pdsu.shop.pojo.goods;
import edu.pdsu.shop.service.ShopService;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.List;

/**
 * 购物车小程序
 *      购物车删除功能的实现
 */
@WebServlet("/deleteCarGoods")
public class CarServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();

        ShopService service = new ShopService();
        //获取前端传来的参数
        String carGoodsName = request.getParameter("carGoodsName");

        //获取session存储域中的购物车List
        HttpSession session = request.getSession();
        List<CarGoods> carGoodsList = (List<CarGoods>) session.getAttribute("carGoodsList");
        //遍历CarGoods集合

        Iterator it = carGoodsList.iterator();
        while(it.hasNext()){
            CarGoods carGoods = (CarGoods) it.next();
            if(carGoods.getCarGoodsName().equals(carGoodsName)){
                //在集合中找到要删除的商品,删除商品
                it.remove();
                //删除后还需要更新数据库中的商品库存数量
                int buyCount = carGoods.getBuyCount();
                goods good = service.selectByGoodsNameService(carGoodsName);
                good.setGoodsCount(good.getGoodsCount() + buyCount);
                try {
                    service.AddGoodsCountService(good);
                } catch (UpdateErrorException e) {
                    e.printStackTrace();
                }
                break;
            }
        }
        //更新购物车的信息
        //删除购物车中的商品的时候，商品的总价格是需要改变的
        double money = 0;
        for (int i = 0; i < carGoodsList.size(); i++) {
            double carGoodsPrice = carGoodsList.get(i).getCarGoodsPrice();
            int buyCount = carGoodsList.get(i).getBuyCount();
            money += carGoodsPrice * buyCount;
        }


        request.setAttribute("money",money);
        request.getRequestDispatcher("/shopcar.jsp").forward(request,response);


    }
}

JudgeCarServlet.java(此处主要用于AJAX异步请求判断购物车状态,具体实现可以参考shoplist.jsp)

package edu.pdsu.shop.servlet;

import edu.pdsu.shop.pojo.CarGoods;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

/**
 * 使用Ajax请求判断购物车是否为空
 *      如果为空想前端响应为空的信息（“购物车为空”）
 */
@WebServlet("/judgecar")
public class JudgeCarServlet extends HttpServlet {
    @Override
    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();
        List<CarGoods> carGoodsList = (List<CarGoods>)session.getAttribute("carGoodsList");
        if(carGoodsList.isEmpty()){
            out.print("购物车为空");
        }
    }
}

以上大致为项目主要的内容,感谢阅读,希望能帮到大家

 

 

# mybatis # java # mysql # servlet # tomcat
Logo
GitCode 开源社区

旨在为数千万中国开发者提供一个无缝且高效的云端环境，以支持学习、使用和贡献开源项目。

更多推荐

[转载]在Windows环境下安装GNU Radio

转自：在Windows环境下安装GNURadio_恐弱智_新浪博客GNU Radio是用Python开发的，大部分开源的工程能够在Linux环境下运行良好，而Windows下却运行的很勉强，而且安装配置都很复杂。GNU Radio算是个例外了，不光提供了Windows的二进制安装，还有比较详细的说明。我是Python小白，所以折腾了好久才弄好，特意记录下来，免得以后再装还折腾。GNU Radio的

avatar GitCode 开源社区

centOS 8 使用dnf安装Docker

DNF是什么？CentOS 8使用YUM软件包管理器版本v4.0.4。现在，该版本使用DNF(已删除YUM)。DNF是软件包管理器。它会在Linux发行版上安装，执行更新并删除软件包。使用DNF安装Docker跳过具有损坏依赖性的程序包一个有效的解决方案是使您的CentOS 8系统使用以下--nobest命令安装最符合条件的版本：sudo dnf install docker...

avatar GitCode 开源社区

定时同步数据库表(mysql+linux+crontab)

sync.sh里面的参数需要改变，ip/username/password/database/tablesync.sh#!/bin/sh# Please change the IP and password of the data source db.# Then change the table name.filename=/home/nington/db/$(date +%Y-%m

avatar GitCode 开源社区