尚硅谷网上书城项目概要

1.项目简介

书城项目采用MVC设计模式，软件三层架构。
①表现层：接受用户的请求，调用业务逻辑层处理用户请求，显示处理结果。对应着View视图（jsp）与Controller控制器（servlet实现）。
②业务逻辑层：调用数据访问层处理业务逻辑，采用面向接口编程思想，先定义接口，在创建实现类。
③数据访问层：用来操作数据库，对数据库进行增删改查。采用面向接口编程的思想，先定义接口，再创建实现类。②和③加上实体类模型对应着Model模型，负责各个功能的实现。
采用三层架构可以明显降低耦合度，便于维护以及扩展开发；但是也降低了系统的性能，以及增加了代码量。
本项目实现了用户通过浏览器访问以及注册或者登录书城的功能，用户可以在书城中浏览图书，添加购物车以及提交订单等操作，管理员可以对书城的图书进行增删改查等操作。
本项目采用MySQL数据库进行数据管理以及数据库表的设计。

部分界面如下：
主界面：

登录界面：如果输入错误，用户信息回显到输入框，并提示用户。

注册界面：输入用户名后，会有相应的提示。

登陆成功，session域中保存了用户信息，显示到界面。添加购物车后，界面会有提示信息

购物车：

2.根据需求分阶段实现项目

在项目的开始阶段，我们需要创建项目需要的数据库：
这是用户表：

CREATE DATABASE book;
CREATE TABLE t_user(id INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(100) NOT NULL UNIQUE,
`password` VARCHAR(32) NOT NULL,
email VARCHAR(200));

这是书籍表：

CREATE TABLE t_book(id INT PRIMARY KEY AUTO_INCREMENT,`name` VARCHAR(100),price DECIMAL(11,2),author VARCHAR(100),sales INT,stock INT,img_path VARCHAR(200));

这是订单表以及订单项表：

CREATE TABLE t_order(order_id VARCHAR(50) PRIMARY KEY,create_time DATETIME,price DECIMAL(11,2),`status` INT,user_id INT,FOREIGN KEY(user_id) REFERENCES t_user(id));CREATE TABLE t_order_item(id INT PRIMARY KEY AUTO_INCREMENT,`name` VARCHAR(100),`count` INT,price DECIMAL(11,2),`total_price` DECIMAL(11,2),order_id VARCHAR(50),FOREIGN KEY(order_id) REFERENCES t_order(order_id)
);

然后就是创建包，项目结构如下：

第一阶段：表单验证
例如项目要求密码必须由字母，数字，下划线组成，并且长度为5到12位。

 // 验证密码：必须由字母，数字下划线组成，并且长度为5到12位//1 获取用户名输入框里的内容var passwordText = $("#password").val();//2 创建正则表达式对象var passwordPatt = /^\w{5,12}$/;//3 使用test方法验证if (!passwordPatt.test(passwordText)) {//4 提示用户结果$("span.errorMsg").text("密码不合法！");return false;}

第二阶段：实现用户的注册和登录

我们已经创建好了用户表，根据用户表在pojo包里创建javaBean实例：

public class User {private int id;private String username;private String password;private String email;

并创建构造器，get/set等方法。
进行分层编写，dao层进行与数据库交互，service层处理业务逻辑并调用dao层方法：

public interface UserDao {/*** 根据用户名查询用户信息** @param username* @return 如果返回null则说明没有查到*/public User queryUsername(String username);/*** 根据用户名和密码查询** @param username* @param password* @return null 表示没有查到*/public User queryUserByUsernameAndPassword(String username, String password);/*** 保存用户信息** @return*/public int saveUser(User user);
}

编写实现类，实现该接口：

public class UserDaoImpl extends BaseDao implements UserDao {@Overridepublic User queryUsername(String username) {String sql = "select id,username,password,email from t_user where username = ?";return queryForOne(User.class,sql,username);}@Overridepublic User queryUserByUsernameAndPassword(String username, String password) {String sql = "select id,username,password,email from t_user where username = ? and password = ?";return queryForOne(User.class,sql,username,password);}@Overridepublic int saveUser(User user) {String sql = "insert into t_user(username,password,email) values (?,?,?)";return update(sql,user.getUsername(),user.getPassword(),user.getEmail());}
}

service层里接口和实现类如下：

package com.atguigu.service;import com.atguigu.pojo.User;/*** @author: SunXiaolin* @create: 2021-04-13-12:03*/
public interface UserService {/*** 注册用户* @param user*/public void registerUser(User user);/*** 登录* @param user* @return 如果返回null说明登录失败*/public User login(User user);/*** 检查用户名是否可用* @param username* @return 返回true表示用户名已存在*/public boolean existUsername(String username);}

实现类：

package com.atguigu.service.impl;import com.atguigu.dao.UserDao;
import com.atguigu.dao.impl.UserDaoImpl;
import com.atguigu.pojo.User;
import com.atguigu.service.UserService;/*** @author: SunXiaolin* @create: 2021-04-13-12:24*/
public class UserServiceImpl implements UserService {private UserDao userDao = new UserDaoImpl();@Overridepublic void registerUser(User user) {userDao.saveUser(user);}@Overridepublic User login(User user) {return userDao.queryUserByUsernameAndPassword(user.getUsername(),user.getPassword());}@Overridepublic boolean existUsername(String username) {if (userDao.queryUsername(username) == null){//等于null说明没有查到，表示可用return false;}else{return true;}}
}

接下来就可以编写web层了：这里form表单跳转到userServlet程序，并发送了一个隐藏的action，值为register，从而调用servlet程序的注册方法

 <form action="userServlet" method="post"><input type="hidden" name="action" value="register"/><label>用户名称：</label><input class="itxt" type="text" placeholder="请输入用户名"value="${requestScope.username}"autocomplete="off" tabindex="1" name="username" id="username"/><br/><br/><label>用户密码：</label><input class="itxt" type="password" placeholder="请输入密码"autocomplete="off" tabindex="1" name="password" id="password"/><br/><br/><label>确认密码：</label><input class="itxt" type="password" placeholder="确认密码"autocomplete="off" tabindex="1" name="repwd" id="repwd"/><br/><br/><label>电子邮件：</label><input class="itxt" type="text" placeholder="请输入邮箱地址"value="${requestScope.email}"autocomplete="off" tabindex="1" name="email" id="email"/><br/><br/><label>验证码：</label><input class="itxt" type="text" name="code" style="width: 80px;" id="code"/><img id="code_img" alt="" src="kaptcha.jpg" style="float: right; margin-right: 40px;width:110px;height: 30px;
"><br/><br/><input type="submit" value="注册" id="sub_btn"/></form>

进入到servlet程序后，如下：不符合要求的返回注册页面，通过验证则调用service层方法，进而调用dao方法，从而将用户信息保存到数据库。

protected void register(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//获取Session中的验证码String token = (String) req.getSession().getAttribute(KAPTCHA_SESSION_KEY);//删除Session中的验证码，防止复用req.getSession().removeAttribute(KAPTCHA_SESSION_KEY);//1.获取请求的参数String username = req.getParameter("username");String password = req.getParameter("password");String email = req.getParameter("email");String code = req.getParameter("code");System.out.println(666);User user = WebUtils.copyParamToBean(req.getParameterMap(),new User());//2.检查验证码是否正确   if (token != null && token.equalsIgnoreCase(code)) {if (userService.existUsername(username)) {req.setAttribute("msg", "用户名已存在");req.setAttribute("username", username);req.setAttribute("email", email);req.getRequestDispatcher("pages/user/regist.jsp").forward(req, resp);} else {userService.registerUser(new User(username, password, email));req.getRequestDispatcher("pages/user/regist_success.jsp").forward(req, resp);}} else {//把回显信息，保存到request域中req.setAttribute("msg", "验证码不正确");req.setAttribute("username", username);req.setAttribute("email", email);//验证码不正确req.getRequestDispatcher("pages/user/regist.jsp").forward(req, resp);}

关于图书模块，大体和如上思路一样。
如下是bookservlet程序：

package com.atguigu.web;import com.atguigu.pojo.Book;
import com.atguigu.pojo.Page;
import com.atguigu.service.BookService;
import com.atguigu.service.impl.BookServiceImpl;
import com.atguigu.utils.WebUtils;import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;/*** @author: SunXiaolin* @create: 2021-04-18-13:04*/
public class BookServlet extends BaseServlet {BookService bookService = new BookServiceImpl();protected void add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {int pageNo = WebUtils.parseInt(req.getParameter("pageNo"),0);pageNo += 1;//1.获取请求的参数，封装成book对象Book book = WebUtils.copyParamToBean(req.getParameterMap(),new Book());//2.调用BookService.addBook()保存图书bookService.addBook(book);//3.跳到图书列表页面 /manager/bookServlet?action=list//重定向resp.sendRedirect(req.getContextPath()+"/manager/bookServlet?action=page&pageNo=" + pageNo);}protected void update(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.获取请求参数，封装成Book对象Book book = WebUtils.copyParamToBean(req.getParameterMap(), new Book());//2.调用BookService.updateBook方法，修改图书bookService.updateBook(book);//3.重定向回图书列表管理页面resp.sendRedirect(req.getContextPath()+"/manager/bookServlet?action=page&pageNo=" + req.getParameter("pageNo"));}protected void getBook(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.获取请求的参数图书编号int id = WebUtils.parseInt(req.getParameter("id"),0);//2.调用bookService.queryBookById()查询图书Book book = bookService.queryBookById(id);//3.保存到request域中req.setAttribute("book",book);//4.请求转发到pages/manager/book_edit.jspreq.getRequestDispatcher("/pages/manager/book_edit.jsp").forward(req,resp);}protected void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.获取请求的参数id，图书编号int id = WebUtils.parseInt(req.getParameter("id"),0);//2.调用bookService.deleteBookById方法。删除图书bookService.deleteBookById(id);//3.重定向图书列表管理页面 /book/manager/bookServlet?action=listresp.sendRedirect(req.getContextPath()+"/manager/bookServlet?action=page&pageNo=" + req.getParameter("pageNo"));}protected void list(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.通过bookService查询全部图书List<Book> books = bookService.queryBooks();//2.把全部图书保存到request域中req.setAttribute("books",books);//3.请求转发到/pages/manager/book_manager.jsp页面req.getRequestDispatcher("/pages/manager/book_manager.jsp").forward(req,resp);}/*** 处理分页功能* @param req* @param resp* @throws ServletException* @throws IOException*/protected void page(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//1.获取请求的参数pageNo、pageSizeint pageNo = WebUtils.parseInt(req.getParameter("pageNo"),1);int pageSize = WebUtils.parseInt(req.getParameter("pageSize"), Page.PAGE_SIZE);//2.调用BookService.page(pageNo，pageSize) page对象Page<Book> page = bookService.page(pageNo,pageSize);page.setUrl("manager/bookServlet?action=page");//3.保存page对象到request域中req.setAttribute("page",page);//4.请求转发到pages/manager/book_manager.jsp页面req.getRequestDispatcher("/pages/manager/book_manager.jsp").forward(req,resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {super.doPost(req,resp);}}

购物车部分采用的是session实现，把购物车信息保存到session域中：

 protected void addItem(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// 获取请求的参数 商品编号int id = WebUtils.parseInt(req.getParameter("id"), 0);// 调用 bookService.queryBookById(id):Book 得到图书的信息Book book = bookService.queryBookById(id);// 把图书信息，转换成为 CartItem 商品项CartItem cartItem = new CartItem(book.getId(), book.getName(), 1, book.getPrice(), book.getPrice());// 调用 Cart.addItem(CartItem);添加商品项Cart cart = (Cart) req.getSession().getAttribute("cart");//        System.out.println(req.getSession().isNew());if (cart == null) {cart = new Cart();}req.getSession().setAttribute("cart", cart);cart.addItem(cartItem);//        System.out.println(cart);
//        System.out.println("请求头 Referer 的值：" + req.getHeader("Referer"));// 重定向回原来商品所在的地址页面resp.sendRedirect(req.getHeader("Referer"));//最后一个添加的名称req.getSession().setAttribute("lastName", cartItem.getName());}

关于订单模块思路介绍：

根据上图逐步实现各个方法。servlet部分如下：

package com.atguigu.web;import com.atguigu.pojo.Cart;
import com.atguigu.pojo.Order;
import com.atguigu.pojo.OrderItem;
import com.atguigu.pojo.User;
import com.atguigu.service.OrderService;
import com.atguigu.service.impl.OrderServiceImpl;
import com.atguigu.utils.JDBCUtils;
import com.atguigu.utils.WebUtils;import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;/*** @author: SunXiaolin* @create: 2021-04-28-21:48*/
public class OrderServlet extends BaseServlet {//创建service实例OrderService orderService = new OrderServiceImpl();//删除所有订单protected void deleteOrders(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));orderService.deleteOrder(orderId);resp.sendRedirect(req.getContextPath()+"/orderServlet?action=showMyOrders");}//删除一个订单protected void deleteOrder(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));orderService.deleteOrder(orderId);resp.sendRedirect(req.getContextPath()+"/orderServlet?action=showAllOrders");}//订单已到货，修改订单状态protected void arrive(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));orderService.arrive(orderId);req.getRequestDispatcher("/pages/order/trans.jsp").forward(req,resp);}/*** 签收* @param req* @param resp* @throws ServletException* @throws IOException*/protected void receiveOrder(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));orderService.receiveOrder(orderId);resp.sendRedirect(req.getContextPath()+"/orderServlet?action=showMyOrders");}//查看我的订单protected void showMyOrders(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {User loginUser = (User) req.getSession().getAttribute("user");if (loginUser == null){req.getRequestDispatcher("/pages/user/login.jsp").forward(req,resp);return;}int userId = loginUser.getId();List<Order> orders = orderService.showMyOrders(userId);req.getSession().setAttribute("orders",orders);resp.sendRedirect(req.getContextPath()+"/pages/order/order.jsp");}/*** 发货* @param req* @param resp* @throws ServletException* @throws IOException*/protected void sendOrder(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));orderService.sendOrder(orderId);resp.sendRedirect(req.getContextPath()+"/orderServlet?action=showAllOrders");}/*** 查看订单详情* @param req* @param resp* @throws ServletException* @throws IOException*/protected void showOrderDetail(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String orderId = WebUtils.parseString(req.getParameter("orderId"));List<OrderItem> orderItems = orderService.showOrderDetail(orderId);req.setAttribute("orderItems",orderItems);req.getRequestDispatcher("/pages/order/orderDetails.jsp").forward(req,resp);}/*** 查看所有订单* @param req* @param resp* @throws ServletException* @throws IOException*/protected void showAllOrders(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {List<Order> orders = orderService.showAllOrders();req.getSession().setAttribute("orders",orders);req.getRequestDispatcher("/pages/manager/order_manager.jsp").forward(req,resp);}/*** 生成订单* @param req* @param resp* @throws ServletException* @throws IOException*/protected void createOrder(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//先获取cart购物车对象Cart cart = (Cart) req.getSession().getAttribute("cart");//获取userIdUser loginUser = (User) req.getSession().getAttribute("user");if (loginUser == null){req.getRequestDispatcher("/pages/user/login.jsp").forward(req,resp);return;}int userId = loginUser.getId();//调用orderService.createOrder(Cart,UserId)方法，生成订单String orderId = orderService.createOrder(cart, userId);//        req.setAttribute("orderId",orderId);重定向后不能共享，改用session//请求转发到pages/cart/checkout.jsp页面
//        req.getRequestDispatcher("/pages/cart/checkout.jsp").forward(req,resp); 表单重复提交req.getSession().setAttribute("orderId",orderId);resp.sendRedirect(req.getContextPath()+"/pages/cart/checkout.jsp");}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {super.doPost(req, resp);}
}

完整项目代码以及jar包请参考：https://github.com/sxlin2021
才疏学浅，多谢指教。