这篇文章主要介绍“JavaWeb购物车项目如何开发”，在日常操作中，相信很多人在JavaWeb购物车项目如何开发问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”JavaWeb购物车项目如何开发”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
一、项目前提
购物车并不是一直放数据库
选择使用的技术：
session：（购物车项目使用session）
好处:快(放在内存当中)，存对象的
坏处:占用内存，服务器意外待机数据会丢失cookie
好处：不占用内存，存储很久
坏处：存在客户端上，只能存String,数据有泄露的风险
二、数据库的创建
用户表
create table shop_user ( id number primary key,--用户id account varchar2(30) not null,--用户账户 password varchar2(30)not null--用户密码);商品表
create table shop_goods( id number primary key,--商品id name varchar2(50) not null,--商品名称 price number default 0.0,--商品价格 info varchar2(255) default '三五产品' not null--商品介绍 );三、eclipse进行创建包和类：
com.zking.util 帮助类com.zking.pojo 实体类com.zking.dao（放dao接口）com.zking.dao.imp (放dao接口实现类)com.zking.biz （业务逻辑层放dao方法）com.zking.biz.imp（业务逻辑层放dao实现类） com.zking.vo (view object 视图对象 前端用)
四、主要实现功能
1、购物车用户登录
login.jsp
界面效果
代码如下：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html><html lang="zh"><head> <meta charset="UTF-8"> <title>Document</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/css/bootstrap.css" rel="external nofollow" rel="external nofollow" > <script src="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/js/jquery-3.5.1.js"></script> <script src="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/js/bootstrap.js"></script> <style> * { outline: none !important; } html, body { background: #1abe9c; } form { width: 300px; background: #ebeff2; box-shadow: 0px 0px 50px rgba(0, 0, 0, .5); border-radius: 5px; padding: 20px; position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%); } .btn-group { width: 100%; } .btn-group button { width: 50%; } </style></head> <body><form action="doLogin.jsp" method="post"> <h4 class="text-center" >欢迎光临苡桉超市</h4> <div class="form-group"> <input name="account" type="text" class="form-control" placeholder="请输入您的用户名"> </div> <div class="form-group"> <input name="password" type="password" class="form-control" placeholder="请输入您的密码"> </div> <div class="btn-group"> <button type="submit" class="btn btn-primary">登录</button> <button type="button" class="btn btn-danger">没有账号?</button> </div></form></body></html>doLogin.jsp(处理登录界面)
<%@page import="com.zking.vo.CarItem"%><%@page import="java.util.ArrayList"%><%@page import="java.util.List"%><%@page import="com.zking.pojo.User"%><%@page import="com.zking.biz.impl.UserBizImpl"%><%@page import="com.zking.biz.IUserBiz"%><%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><% request.setCharacterEncoding("UTF-8"); String account=request.getParameter("account"); String password=request.getParameter("password"); IUserBiz userBiz=new UserBizImpl(); User user=userBiz.login(new User(0,account,password)); if(user==null){ response.sendRedirect("login.jsp"); }else{ //首页需要登录数据 session.setAttribute("user",user); //分配购物车 List<CarItem>car=new ArrayList<>(); //放到session中（把购物车给我） session.setAttribute("car", car); response.sendRedirect("index.jsp"); }%>用户实体类User.java
package com.zking.pojo; public class User { private Integer id; private String account; private String password;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getAccount() {return account;}public void setAccount(String account) {this.account = account;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public User(Integer id, String account, String password) {super();this.id = id;this.account = account;this.password = password;}public User() {super();}@Overridepublic String toString() {return "User [id=" + id + ", account=" + account + ", password=" + password + "]";}}IUserBiz.java (用户逻辑接口)
package com.zking.biz; import com.zking.pojo.User;public interface IUserBiz { User login(User user);}UserBizImpl.java (用户逻辑接口实现类)
package com.zking.biz.impl; import com.zking.biz.IUserBiz;import com.zking.dao.IUserDao;import com.zking.dao.impl.UserDaoImpl;import com.zking.pojo.User;public class UserBizImpl implements IUserBiz{ private IUserDao userDao=new UserDaoImpl();@Overridepublic User login(User user) {User u = userDao.login(user);if(u!=null) {if(u.getPassword().equals(user.getPassword())) {return u;}}return null;}}IUserDao.java（用户数据访问接口）
package com.zking.dao; import com.zking.pojo.User;public interface IUserDao {User login(User user);}UserDaoImpl.java（用户数据访问接口实现类）
package com.zking.dao.impl; import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.List; import com.zking.dao.IUserDao;import com.zking.pojo.User;import com.zking.util.DBHelper; public class UserDaoImpl implements IUserDao { private Connection con;private PreparedStatement ps;private ResultSet rs;@Override public User login(User user) {try { con=DBHelper.getCon(); ps=con.prepareStatement("select * from shop_user where account=?"); ps.setString(1,user.getAccount()); rs=ps.executeQuery(); if(rs.next()) { User u=new User(); u.setId(rs.getInt(1)); u.setAccount(rs.getString(2)); u.setPassword(rs.getString(3)); return u; }} catch (Exception e) { e.printStackTrace();}finally {DBHelper.close(con, ps, rs);} return null; }}2、商品显示
实现效果如下：
将数据库存放的数据显示在页面上，尊贵的xxx通过session拿到登录的用户名
Goods.java（商品实体类）
package com.zking.pojo; public class Goods { private Integer id; private String name; private Integer price; private String info;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getPrice() {return price;}public void setPrice(Integer price) {this.price = price;}public String getInfo() {return info;}public void setInfo(String info) {this.info = info;}public Goods(Integer id, String name, Integer price, String info) {super();this.id = id;this.name = name;this.price = price;this.info = info;}public Goods() {super();}@Overridepublic String toString() {return "Goods [id=" + id + ", name=" + name + ", price=" + price + ", info=" + info + "]";}}index.jsp（首页代码）
<%@page import="com.zking.pojo.Goods"%><%@page import="com.zking.biz.impl.GoodsBizImpl"%><%@page import="com.zking.biz.IGoodsBiz"%><%@page import="com.zking.pojo.User"%><%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><!DOCTYPE html><html lang="zh"><head> <meta charset="UTF-8"> <title>Document</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/css/bootstrap.css" rel="external nofollow" rel="external nofollow" > <script src="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/js/jquery-3.5.1.js"></script> <script src="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/js/bootstrap.js"></script> <style> td:nth-child(3)::before{ content: "$"; } </style></head> <body><% Object obj=session.getAttribute("user"); if(obj==null){ response.sendRedirect("login.jsp"); return; }%> <div class="jumbotron"> <div class="container"> <h2>欢迎光临苡桉SuperMarket</h2> <p>尊贵的<%=((User)obj).getAccount() %></p> </div> </div> <%=session.getAttribute("car")%> <div class="container"> <table class="table"> <tr> <th>商品序号</th> <th>商品名称</th> <th>商品单价</th> <th>商品描述</th> <th>操作</th> </tr> <% IGoodsBiz goodsBiz=new GoodsBizImpl(); for(Goods goods:goodsBiz.getAll()){ %> <tr> <td><%=goods.getId() %></td> <td><%=goods.getName() %></td> <td><%=goods.getPrice() %></td> <td><%=goods.getInfo() %></td> <td> <div class="btn-group btn-group-xs"> <a href="doAddCar.jsp?id=<%=goods.getId() %>" rel="external nofollow" class="btn btn-primary">添加购物车</a> </div> </td> </tr> <% } %> </table> </div></body></html>IGoodsBiz.java (商品逻辑接口)
package com.zking.biz;import java.util.List;import com.zking.pojo.Goods;public interface IGoodsBiz { List<Goods>getAll(); //查询单个 Goods getOne(Integer id);}GoodsBizImpl.java (商品逻辑接口实现类)
package com.zking.biz.impl; import java.util.List; import com.zking.biz.IGoodsBiz;import com.zking.dao.IGoodsDao;import com.zking.dao.impl.GoodsDaoImpl;import com.zking.pojo.Goods;public class GoodsBizImpl implements IGoodsBiz { private IGoodsDao goodsDao=new GoodsDaoImpl();@Overridepublic List<Goods> getAll() {return goodsDao.getAll(); } @Overridepublic Goods getOne(Integer id) {return goodsDao.getOne(id);}}IGoodsDao.java (商品数据访问接口)
package com.zking.dao;import java.util.List;import com.zking.pojo.Goods;public interface IGoodsDao {//查询所有 List<Goods>getAll(); //查询单个 Goods getOne(Integer id);}GoodsDaoImpl.java (商品数据访问接口实现类)
package com.zking.dao.impl;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;import com.zking.dao.IGoodsDao;import com.zking.pojo.Goods;import com.zking.pojo.User;import com.zking.util.DBHelper;public class GoodsDaoImpl implements IGoodsDao{private Connection con;private PreparedStatement ps;private ResultSet rs;@Overridepublic List<Goods> getAll() {List<Goods>list=new ArrayList<Goods>();try { con=DBHelper.getCon(); ps=con.prepareStatement("select * from shop_goods "); rs=ps.executeQuery(); while(rs.next()) { Goods goods=new Goods(); goods.setId(rs.getInt(1)); goods.setName(rs.getString(2)); goods.setPrice(rs.getInt(3)); goods.setInfo(rs.getString(4)); list.add(goods); } return list;} catch (Exception e) { e.printStackTrace();}finally {DBHelper.close(con, ps, rs);}return list;} @Overridepublic Goods getOne(Integer id) { try { con=DBHelper.getCon(); ps=con.prepareStatement("select * from shop_goods where id=? "); ps.setInt(1, id); rs=ps.executeQuery(); if(rs.next()) { Goods goods=new Goods(); goods.setId(rs.getInt(1)); goods.setName(rs.getString(2)); goods.setPrice(rs.getInt(3)); goods.setInfo(rs.getString(4)); return goods; } } catch (Exception e) { e.printStackTrace();}finally {DBHelper.close(con, ps, rs);}return null;}}3、购物车添加&商品总数和价格的计算
doAddCar.java(处理添加购物车的页面)
<%@page import="java.util.List"%><%@page import="com.zking.biz.impl.GoodsBizImpl"%><%@page import="com.zking.biz.IGoodsBiz"%><%@page import="com.zking.vo.CarItem"%><%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><% //添加购物车的页面 //拿购物车 List<CarItem>car=(List<CarItem>)session.getAttribute("car"); IGoodsBiz goodsBiz=new GoodsBizImpl(); //1、得知道是那件商品 String str=request.getParameter("id"); int id=-1; if(str!=null){ id=Integer.parseInt(str); } //2-1 判断该商品是否存在 boolean f=true; for(CarItem item:car){ //item.getGoods().getId() 条目的商品id if(id==item.getGoods().getId()){ //商品应该是已经被添加了[购物车中某个条目的商品id和你需要添加的商品id相同了] item.setCount(item.getCount()+1);//数量+1 item.setSum(item.getCount()*item.getGoods().getPrice()); f=false; break; } } //只要判断f是否发生了改变 if(f){ //2-2、生成一个CarItem[如果购物车没有该商品] CarItem carItem=new CarItem(); //设置对应的商品数据 carItem.setGoods(goodsBiz.getOne(id)); //数量 carItem.setCount(1); //加车数量*商品单价 //carItem.getCount()商品加车的数量 //carItem.getGoods().getPrice() 商品的单价 carItem.setSum(carItem.getCount()*carItem.getGoods().getPrice()); //将购物条目carItem 绑定到购物车 car.add(carItem); } //更新购物车 session.setAttribute("car", car); //跳回首页 response.sendRedirect("index.jsp");%>CarItem.java（购物车中的每一项，每一个条目）
package com.zking.vo; import com.zking.pojo.Goods; public class CarItem { private Integer count;//数量private Integer sum;//条目总价private Goods goods;//对应的商品public Integer getCount() {return count;}public void setCount(Integer count) {this.count = count;}public Integer getSum() {return sum;}public void setSum(Integer sum) {this.sum = sum;}public Goods getGoods() {return goods;}public void setGoods(Goods goods) {this.goods = goods;}public CarItem(Integer count, Integer sum, Goods goods) {super();this.count = count;this.sum = sum;this.goods = goods;}public CarItem() {// TODO Auto-generated constructor stub}@Overridepublic String toString() {return "CarItem [count=" + count + ", sum=" + sum + ", goods=" + goods + "]";}}效果先简单打印到页面 之后会进行修改
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