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JavaWeb程序设计之JSP实现购物车功能全过程

 更新时间：2025年01月04日 10:04:36   作者：布丁椰奶冻  
这篇文章主要介绍了如何使用Java和相关技术实现一个基本的购物车功能,包括商品列表展示、用户登录、结账和查看购物车等功能,通过编写代码和设计JSP页面,实现了用户交互和数据管理,需要的朋友可以参考下

一、结合之前所学的相关技术，编写代码实现以下购物车功能

1. 编写一个页面，展现商品列表（静态页面），页面右上方有登陆、结账和查看购物车三个按钮，下方展示网站历史访问的人数

2. 用户点击商品后，可以将商品加入购物车

3. 用户点击登陆，跳转到登陆页面

4. 用户点击结账，若已登陆跳转至结账页面，否则跳转到登陆页面登陆后再跳转到结账页。

5. 用户点击查看购物车按钮，跳转至购物车页面，可查看购物车列表、增加商品数量或者删除商品

1. 我实现的功能运行截图如下

（1）商品列表页面home.jsp

（2）登录账号页面/未登录点击结账页面

（3）重新登录页面（记住上次登录的用户名和密码）

（4）点击任意商品加入购物车之后查看购物车

（5）增加或减少商品

（6）商品数量减为0时移除

（7）点击去结算，展示总金额

2. 数据库test存放的表格

（1）user表

（2）product表

导入jar包 

3. 实体类

（1）User

package com.ryx.web.sy7;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@NoArgsConstructor
@AllArgsConstructor
@Data
@Builder
public class User {
    private String username;
    private String password;
}

（2）Product.java

package com.ryx.web.sy7;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Product {
    Integer id;
    String name;
    String imagePath;
    BigDecimal price;
    String description;
}

（3）ProductVo

package com.ryx.web.sy7;

import lombok.Getter;
import lombok.Setter;
import java.math.BigDecimal;

public class ProductVo extends Product {
    @Getter
    @Setter
    Integer count; //统计数量

    public ProductVo(Integer id, Integer count, String name, double price, String imagePath) {
        super();
        this.id = id;
        this.count = count;
        this.name = name;
        this.price = BigDecimal.valueOf(price);
        this.imagePath=imagePath;
    }
}

4. CartController.java

package com.ryx.web.sy7;

import lombok.SneakyThrows;
import org.springframework.util.ObjectUtils;
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;
import java.io.IOException;
import java.sql.*;
import java.util.HashMap;
import java.util.Map;

@WebServlet(name = "shoppingCart", value = "/shoppingCart")
public class CartController extends HttpServlet {
//    连接数据库
    private static final String DB_URL = "jdbc:mysql://localhost:3306/test";
    private static final String DB_USERNAME = "root";
    private static final String DB_PASSWORD = "abc1234";

    @SneakyThrows
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Integer id = Integer.valueOf(request.getParameter("id"));
        String op = request.getParameter("op");
        String whereCome = request.getHeader("Referer");
        String redirectPath = null;
//        如果在主页点击加入购物车超链接，不跳转
        if (whereCome.equals("http://localhost:8080/sy7/home.jsp")) {
            redirectPath = request.getContextPath() + "/sy7/home.jsp";
        } else {
//            如果在购物车页面增加或删除商品也不跳转
            redirectPath = request.getContextPath() + "/sy7/cart.jsp";
        }
        HttpSession session = request.getSession();
        Map<Integer, ProductVo> cart = (Map<Integer, ProductVo>) session.getAttribute("cart");
        if (ObjectUtils.isEmpty(cart)) {
            cart = new HashMap();
        }
        switch (op) {
//            添加商品
            case "add":
                if (!ObjectUtils.isEmpty(cart.get(id))) {
                    ProductVo productVo = cart.get(id);
                    productVo.setCount(productVo.getCount() + 1);
                    cart.put(id, productVo);
                } else {
                    Class.forName("com.mysql.jdbc.Driver");
                    try (Connection conn = DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD)) {
                        String query = "SELECT * FROM product WHERE id = ?";
                        try (PreparedStatement stmt = conn.prepareStatement(query)) {
                            stmt.setInt(1, id);
                            try (ResultSet rs = stmt.executeQuery()) {
                                if (rs.next()) {
                                    String name = rs.getString("name");
                                    double price = rs.getDouble("price");
                                    String imagePath = rs.getString("image_path");
                                    Integer iid = rs.getInt("id");
                                    ProductVo productVo = new ProductVo(iid, 1, name, price, imagePath);
                                    cart.put(id, productVo);
                                }
                            }
                        }
                    } catch (SQLException e) {
                        e.printStackTrace();
                    }
                }
                break;
//          减少商品
            case "sub":
                if (!ObjectUtils.isEmpty(cart.get(id))) {
                    ProductVo productVo = cart.get(id);
//                    防止出现负数
                    if (productVo.getCount() > 1) {
                        productVo.setCount(productVo.getCount() - 1);
                        cart.put(id, productVo);
                    } else {
//                        如果小于1则移除商品
                        cart.remove(id);
                    }

                }
                break;
        }
        session.setAttribute("cart", cart);
        response.sendRedirect(redirectPath);
    }
}

5. JSP页面

（1）展现商品列表（home.jsp）

CSS

table {
    border-collapse: collapse;
    width: 86%;
}

table, th, td {
    border: 1px solid gainsboro;
}

td {
    width: 200px;
}

.redText {
    color: #FF0000;
}

.pinkTest {
    color: lightpink;
}

<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.DriverManager" %>
<%--
  Created by IntelliJ IDEA.
  User: 86189
  Date: 2023/10/23
  主页面展示商品
--%>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>小煊的美妆铺</title>
   
</head>
<body>
<h1 align="center" class="pinkTest">欢迎来到小煊的美妆铺~</h1>
<div align="right" style="width: 90%"><a href="login.jsp" rel="external nofollow" >登录</a></div>
<div align="right" style="width: 90%"><a href="checkout.jsp" rel="external nofollow"  rel="external nofollow" >结算</a></div>
<div align="right" style="width: 90%"><a href="cart.jsp" rel="external nofollow" >查看购物车</a></div>
<br>

<table align="center">
    <%---------------------- 获取商品数据 -----------------------------%>
    <%
        Connection conn = null;
        PreparedStatement stmt = null;
        ResultSet rs = null;
        try {
            //连接数据库
            Class.forName("com.mysql.cj.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "abc1234");
            String query = "SELECT * FROM product";
            stmt = conn.prepareStatement(query);
            rs = stmt.executeQuery();

            int count = 0;
            while (rs.next()) {
                int id = rs.getInt("id"); //商品编号
                String name = rs.getString("name"); //商品名
                double price = rs.getDouble("price"); //价格
                String description = rs.getString("description"); //描述
                String imagePath = rs.getString("image_path"); // 图片路径
                //五个商品即换行
                if (count % 5 == 0) {
                    out.println("<tr>");
                }
    %>
    <td><br>
        <%--------------------------图片-----------------------%>
        <div align="center"><img src="<%=request.getContextPath()+imagePath%>" width="180px" height="240px"></div>
        <%--------------------------商品描述-----------------------%>
        <div> <%=name%><%=description%> </div>
        <%--------------------------价格-----------------------%>
        <div class="redText" align="left"> ￥：<%=price%> </div>
        <%--------------------------加购-----------------------%>
        <div align="right">
            <form action="home.jsp" method="post">
                <button onclick="void(0)"><a style="text-decoration: none"
                                             href="<%=request.getContextPath()+" rel="external nofollow" /shoppingCart?id="+id+"&op=add"%>"/>加入购物车
                </button>
            </form>
        </div>
    </td>
    <%
                //闭合标签
                if (count % 5 == 4) {
                    out.println("</tr>");
                }
                count++;
            }
            //最后不足五个，自动闭合
            if (count % 5 != 0) {
                out.println("</tr>");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                rs.close();
            } catch (Exception e) {
            }
            try {
                stmt.close();
            } catch (Exception e) {
            }
            try {
                conn.close();
            } catch (Exception e) {
            }
        }
    %>
</table>
<br>
<%
//    初始化历史访问人数
    Integer accessCount = (Integer) session.getAttribute("accessCount");
    if (accessCount == null) {
        accessCount = new Integer(0);
    } else {
        accessCount = new Integer(accessCount.intValue() + 1);
    }
    session.setAttribute("accessCount", accessCount);
%>

<div>历史访问人数：<%= accessCount %> </div>
</body>
</html>

（2）登陆页面(login.jsp)

JSP程序段＋JS代码

<%-----------------------JSP程序段---------------------------%>
<%
    request.setCharacterEncoding("UTF-8");
    //一次性登录
    String msg = request.getParameter("msg");
%>
<%
    if (msg != null) {
        String errorMessage = "账号或密码有误，请重新输入！";
%>
<script>
    var error = '<%= errorMessage %>';
    alert(error);
</script>
<%
    }
%>

<%-- 读取Cookie --%>
<%
    Cookie[] cookies = request.getCookies();
    String savedUsername = null;
    String savedPassword = null;

    if (cookies != null) {
        for (Cookie cookie : cookies) {
            if (cookie.getName().equals("username")) {
                savedUsername = cookie.getValue();
            } else if (cookie.getName().equals("password")) {
                savedPassword = cookie.getValue();
            }
        }
    }
%>

HTML

<%--
  Created by IntelliJ IDEA.
  User: 86189
  Date: 2023/10/13
  登录页面
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>
<html>
<head>
    <style>
        body {
            display: flex;
            justify-content: center;
            padding-top: 40px;
        }
        .titlecolor{
            color: lightpink;
        }
    </style>
    <title>登录页面</title>
</head>
<body>
<%-----------------------登录表单--------------------------%>
<form action="loginAction.jsp" method="post">
    <h1 align="center" class="titlecolor">登录账号</h1>
    <br>
    <table width="300px">
        <tr>
            <td>
                <laber for="username">用户名：</laber>
            </td>
            <td><input type="text" value="<%= savedUsername==null?"":savedUsername%>" id="username" name="username" required></td>
        </tr>
        <tr>
            <td><label for="password">密码：</label></td>
            <td><input type="password" value="<%= savedPassword==null?"":savedPassword%>" id="password" name="password" required></td>
            <td align="right"><input type="submit" value="登录"></td>
        </tr>
        <tr>
            <td></td>
           <td><input type="checkbox" name="remember" value="member">记住密码</td>
        </tr>
    </table>
</form>

</body>
</html>

（3）登录后台处理页面（loginAction.jsp）

<%@ page import="com.ryx.web.sy7.User" %>
<%@ page import="java.sql.*" %>
<%--
  Created by IntelliJ IDEA.
  User: 86189
  Date: 2023/10/13
  判断输入的用户信息是否存在数据库
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%!
    public boolean validateUser(String username, String password) {
        // 使用JDBC连接数据库
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;

        String driver = "com.mysql.cj.jdbc.Driver";
        String url = "jdbc:mysql://localhost:3306/test";  //数据库
        String user = "root"; //账户
        String psword = "abc1234"; //密码

        try {
            try {
                try {
                    Class.forName(driver);
                } catch (ClassNotFoundException e) {
                    throw new RuntimeException(e);
                }
                // 获取数据库连接
                connection = DriverManager.getConnection(url, user, psword);
            } catch (SQLException e) {
                e.printStackTrace();
            }

            try {
                // 构造查询语句
                String query = "SELECT * FROM test.user WHERE username =  ? ";

                // 创建PreparedStatement对象，并设置参数
                statement = connection.prepareStatement(query);
                statement.setString(1, username);

                // 执行查询
                resultSet = statement.executeQuery();
                // 验证用户名和密码
                if (resultSet.next()) {
                    String storedPassword = resultSet.getString("password");
                    if (storedPassword.equals(password)) {
                        return true;
                    }
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }

        } finally {
            // 关闭连接和释放资源
            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (statement != null) {
                    statement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return false;
    }
 %>

<%
    request.setCharacterEncoding("UTF-8");
    String username = request.getParameter("username");
    String password = request.getParameter("password");

    boolean isValidUser = validateUser(username, password);
    //验证成功
    if (isValidUser) {
        // 创建形 Builder 构造者模式，链式编程
        User user = User.builder()
                    .username(username)
                    .password(password)
                    .build();

        String remember = request.getParameter("remember");

        if (remember != null && remember.equals("member")) {
            // 创建存储用户名和密码的Cookie对象
            Cookie usernameCookie = new Cookie("username", username);
            Cookie passwordCookie = new Cookie("password", password);

            // 设置Cookie的有效期（设置为7天）
            usernameCookie.setMaxAge(7 * 24 * 60 * 60); // 7天
            passwordCookie.setMaxAge(7 * 24 * 60 * 60); // 7天

            // 将Cookie添加到响应中
            response.addCookie(usernameCookie);
            response.addCookie(passwordCookie);
        } else {
            // 删除之前保存的Cookie
            Cookie[] cookies = request.getCookies();
            if (cookies != null) {
                for (Cookie cookie : cookies) {
                    if (cookie.getName().equals("username") || cookie.getName().equals("password")) {
                        cookie.setMaxAge(0); // 设置有效期为0，即立即删除
                        response.addCookie(cookie);
                    }
                }
            }
        }

        session.setAttribute("user", user);
        //跳转到其他页面
        response.sendRedirect("home.jsp");
    } else {
        //验证失败，提示出错
        response.sendRedirect("login.jsp?msg=failed");
    }
 %>

（4）结账页面（checkout.jsp）

HTML+JSP+JSTL

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page import="com.ryx.web.sy7.User" %>
<%@ page import="java.util.Map" %>
<%--
  Created by IntelliJ IDEA.
  User: 86189
  Date: 2023/10/21
  结算页面
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<%--------------------判断用户是否登录-----------------------%>
<%
    //存储变量
    User user = (User) session.getAttribute("user");
    //    未登录用户跳转到登录页面
    if (user == null) {
        response.sendRedirect("login.jsp");
    }
%>
<head>
    <meta charset="UTF-8">
    <title>结算</title>
</head>
<body>
<%----------------- 获取购物车中的商品 ------------------------%>
<h1 align="center" style="color: lightpink">订单信息</h1>
<%
    session = request.getSession();
    Map<Integer, Integer> cart = (Map<Integer, Integer>) session.getAttribute("cart");
    if (cart == null) {
        out.println("购物车为空");
        return;
    }
%>
<%--计算总价钱--%>
<c:set var="totalAmount" value="0"/>
<c:forEach var="entry" items="${cart.entrySet()}">
    <c:set var="product" value="${entry.value}"/>
    <%--单个商品的总额--%>
    <c:set var="amount" value="${product.price * product.count}"/>
    <%--所有商品的总额--%>
    <c:set var="totalAmount" value="${totalAmount + amount}"/>
</c:forEach>
<div align="center">
    <h2>您应支付:￥${totalAmount}</h2>
    <form action="checkout.jsp" method="POST">
        <input type="submit" value="确认订单">
    </form>
</div>

</body>
</html>

（5）购物车页面（cart.jsp）

CSS

table {
    border-collapse: collapse;
}

table, th, td {
    border: 1px solid gainsboro;
}

.titleTest {
    color: lightpink;
}

td {
    width: 20%;
}

a {
   text-decoration: none;
}

HTML

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%--
  Created by IntelliJ IDEA.
  User: 86189
  Date: 2023/10/21
  购物车页面
--%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>购物车</title>

</head>
<body>
<h1 align="center" class="titleTest">我的购物车</h1>
<c:if test="${cart!=null && cart.size()>0}">
    <table style="width: 1000px" align="center">
        <tr>
            <th>商品信息</th>
            <th>单价</th>
            <th>数量</th>
            <th>金额</th>
        </tr>
        <c:forEach var="entry" items="${cart.entrySet()}">
            <tr>
                <c:set var="product" value="${entry.value}"/>
                <%----------------------商品信息--------------------%>
                <td><img src="${request.contextPath}${product.imagePath}" width="60px" height="80px">${product.name}</td>
                <%----------------------单价--------------------%>
                <td align="center">￥：${product.price}</td>
                <%----------------------数量-/+--------------------%>
                <td align="center">
                    <button onclick="void(0)"><a href="
                <%=request.getContextPath()+"/shoppingCart?op=sub&id="%>${product.id}
               "/>-
                    </button>
                        ${product.count}
                    <button onclick="void(0)"><a href="
                <%=request.getContextPath()+"/shoppingCart?op=add&id="%>${product.id}
               "/>+
                    </button>
                </td>
                <%----------------------金额--------------------%>
                <td align="center">￥：${product.count*product.price}</td>

            </tr>

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

<br><br>
<div style="width: 90%" align="right">
    <a href="home.jsp" rel="external nofollow" >继续购物</a>
    <a href="checkout.jsp" rel="external nofollow"  rel="external nofollow" >去结算</a>

</div>
</body>
</html>

总结 

到此这篇关于JavaWeb程序设计之JSP实现购物车功能的文章就介绍到这了,更多相关JSP实现购物车功能内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！

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