昨天给大家讲到要讲解购物车的制作,今天我们就来浅浅的讲解一下吧
目录
一、数据库代码
1.用户表
2.商品表
二、购物车案例
1.项目目录展示
2.项目的编写
💖数据库帮助类:DBHelper
💖用户的实体类:User
💖商品的实体类:Goods
💖user的数据库访问层
💖user的业务逻辑层
💖goods的数据库访问层
💖goods的业务逻辑层
💖登录界面:login.jsp
💖登录处理界面:doLogin.jsp
💖主界面:index.jsp
💖加入购物车:doAddCar.jsp
一、数据库代码
1.用户表
create table shop_user(
s_id number primary key,
s_account varchar2(30) not null,
s_password varchar2(30) not null
)
2.商品表
create table shop_goods(
g_id number primary key,
g_name varchar2(30) not null,
g_price number default 0.0,
g_info varchar2(255) default '三无产品' not null
)
二、购物车案例
1.购物车并不是一直放在数据库
2.选择使用的技术:
session:
好处:快(放在内存中),可以存对象
坏处:占用内存,服务器意外宕机数据会丢失
cookie:
好处:不占用内存,存储很久.....
坏处:存在客户端上,只能存String,数据有泄漏的风险
今天这个案例我是把购物车存储在session中的
1.项目目录展示
2.项目的编写
💖数据库帮助类:DBHelper
package com.xyz.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import oracle.jdbc.driver.OracleDriver;
public class DBHelper {
//1.加载驱动
static {
//OracleDriver
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//2.定义连接字符串
private static final String URL="jdbc:oracle:thin:@localhost:1521:orcl";
//3.获得连接
public static Connection getCon() {
try {
return DriverManager.getConnection(URL,"scott","zkingedu");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
//4.关闭资源
public static void close(Connection con,PreparedStatement ps,ResultSet rs) {
try {
if(con!=null&&!con.isClosed()) {
con.close();
}
if(ps!=null) {
ps.close();
}
if(rs!=null) {
rs.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
System.out.println(DBHelper.getCon());
}
}
💖用户的实体类:User
package com.xyz.pojo;
public class User {
private Integer id;
private String account;
private String password;
public User() {
// TODO Auto-generated constructor stub
}
public User(Integer id, String account, String password) {
super();
this.id = id;
this.account = account;
this.password = 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;
}
@Override
public String toString() {
return "User [id=" + id + ", account=" + account + ", password=" + password + "]";
}
}
💖商品的实体类:Goods
package com.xyz.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() {
// TODO Auto-generated constructor stub
}
public Goods(Integer id, String name, Integer price, String info) {
super();
this.id = id;
this.name = name;
this.price = price;
this.info = info;
}
@Override
public String toString() {
return "Goods [id=" + id + ", name=" + name + ", price=" + price + ", info=" + info + "]";
}
}
💖user的数据库访问层
💕IUserDao接口的编写
package com.xyz.dao;
import com.xyz.pojo.User;
public interface IUserDao {
User login(User user);
}
💕接口的实现:UserDaoImpl
package com.xyz.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import com.xyz.dao.IUserDao;
import com.xyz.pojo.User;
import com.xyz.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 s_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;
}
}
💖user的业务逻辑层
💕IUserBiz接口的编写
package com.xyz.biz;
import com.xyz.pojo.User;
public interface IUserBiz {
User login(User user);
}
💕接口的实现:UserBizImpl
package com.xyz.biz.impl;
import com.xyz.biz.IUserBiz;
import com.xyz.dao.IUserDao;
import com.xyz.dao.impl.UserDaoImpl;
import com.xyz.pojo.User;
public class UserBizImpl implements IUserBiz{
private IUserDao userDao=new UserDaoImpl();
@Override
public User login(User user) {
User u=userDao.login(user);
if(u!=null) {
//u.getPassword()是数据库的字段
if(u.getPassword().equals(user.getPassword())){
return u;
}
}
return null;
}
}
💖goods的数据库访问层
💕IGoodsDao接口的编写
package com.xyz.dao;
import java.util.List;
import com.xyz.pojo.Goods;
public interface IGoodsDao {
//查询所有
List<Goods> getAll();
//根据id查询
Goods getOne(Integer id);
}
💕接口的实现:GoodsDaoImpl
package com.xyz.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import com.xyz.dao.IGoodsDao;
import com.xyz.pojo.Goods;
import com.xyz.pojo.User;
import com.xyz.util.DBHelper;
public class GoodsDaoImpl implements IGoodsDao{
private Connection con;
private PreparedStatement ps;
private ResultSet rs;
//查询所有
@Override
public 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;
}
//根据id查询
@Override
public Goods getOne(Integer id) {
try {
con=DBHelper.getCon();
ps=con.prepareStatement("select * from shop_goods where g_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;
}
}
💖goods的业务逻辑层
💕IGoodsBiz接口的编写
package com.xyz.biz;
import java.util.List;
import com.xyz.pojo.Goods;
public interface IGoodsBiz {
//查询全部
List<Goods> getAll();
//根据id查询
Goods getOne(Integer id);
}
💕接口的实现:GoodsBizImpl
package com.xyz.biz.impl;
import java.util.List;
import com.xyz.biz.IGoodsBiz;
import com.xyz.dao.IGoodsDao;
import com.xyz.dao.impl.GoodsDaoImpl;
import com.xyz.pojo.Goods;
public class GoodsBizImpl implements IGoodsBiz{
private IGoodsDao goodsDao=new GoodsDaoImpl();
@Override
public List<Goods> getAll() {
return goodsDao.getAll();
}
@Override
public Goods getOne(Integer id) {
return goodsDao.getOne(id);
}
}
💖登录界面:login.jsp
<%@ 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="${pageContext.request.contextPath}/bootstrap-3.3.7-dist/css/bootstrap.css">
<script src="${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">
<h3 class="text-center" style="text-shadow: 2px 2px 1px #ed3f3f;">欢迎光临胡阿玛超市</h3>
<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>
💖登录处理界面:doLogin.jsp
<%@page import="com.xyz.vo.CarItem"%>
<%@page import="java.util.ArrayList"%>
<%@page import="java.util.List"%>
<%@page import="com.xyz.pojo.User"%>
<%@page import="com.xyz.biz.impl.UserBizImpl"%>
<%@page import="com.xyz.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
session.setAttribute("car", car);
response.sendRedirect("index.jsp");
}
%>
💖主界面:index.jsp
<%@page import="com.xyz.pojo.Goods"%>
<%@page import="com.xyz.biz.impl.GoodsBizImpl"%>
<%@page import="com.xyz.biz.IGoodsBiz"%>
<%@page import="com.xyz.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">
<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">
<h1>欢迎光临胡阿玛SuperMarket</h1>
<p>尊贵的<%=((User)obj).getAccount() %></p>
</div>
</div>
<!-- 打印一下购物车数据 -->
<%=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() %>" class="btn btn-primary">添加购物车</a>
</div>
</td>
</tr>
<%
}
%>
</table>
</div>
</body>
</html>
💖加入购物车:doAddCar.jsp
<%@page import="java.util.List"%>
<%@page import="com.xyz.biz.impl.GoodsBizImpl"%>
<%@page import="com.xyz.biz.IGoodsBiz"%>
<%@page import="com.xyz.vo.CarItem"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
//拿购物车
List<CarItem> car=(List<CarItem>)session.getAttribute("car");
IGoodsBiz goodsBiz=new GoodsBizImpl();
//添加购物车的页面
//1.得知是哪件商品
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id
if(id==item.getGoods().getId()){
//该商品是已经添加进购物车的[购物车中某个条目的商品id和我添加的商品id是相同的]
item.setCount(item.getCount()+1);
item.setSum(item.getCount()*item.getGoods().getPrice());
f=false;
break;
}
}
//判断f为true
if(f){
// 2-2.生成一个CarItem [如果购物车中没有改商品]
CarItem carItem=new CarItem();
//设置对应的商品数据
carItem.setGoods(goodsBiz.getOne(id));
//数量
carItem.setCount(1);
//总价
//carItem.getCount() 商品数量
//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] 中
car.add(carItem);
}
//更新购物车
session.setAttribute("car", car);
//跳回首页
response.sendRedirect("index.jsp");
%>
今天就讲解到这啦,下次给大家分享优化购物车