Java Web应用案列：蒙西购物

功能需求
1、只有注册用户成功登录之后才可查看商品类别，查看商品，选购商品，生成订单、查看订单。

2、只有管理员才有权限进行购物网后台管理（用户管理+类别管理+商品管理+订单管理）

一、设计思路

1、采用MVC设计模式

2、前台

3、后台

二、运行效果

（一）前台操作

（二）后台操作

三、创建数据库

创建MySQL数据库simonshop，包含四张表：用户表（t_user）、类别表（t_category）、商品表（t_product）和订单表（t_order）。如下：

先新建一个数据库连接名叫：simonshop
再导入外部文件，这里直接新建查询，sql全部代码如下：

/*
Navicat MySQL Data TransferSource Server         : hwsql
Source Server Version : 50518
Source Host           : localhost:3306
Source Database       : simonshopTarget Server Type    : MYSQL
Target Server Version : 50518
File Encoding         : 65001Date: 2017-02-16 09:21:41
*/SET FOREIGN_KEY_CHECKS=0;-- ----------------------------
-- Table structure for `t_category`
-- ----------------------------
DROP TABLE IF EXISTS `t_category`;
CREATE TABLE `t_category` (`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '商品类别标识符',`name` varchar(100) NOT NULL COMMENT '商品类别名称',PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;-- ----------------------------
-- Records of t_category
-- ----------------------------
INSERT INTO `t_category` VALUES ('1', '家用电器');
INSERT INTO `t_category` VALUES ('2', '床上用品');
INSERT INTO `t_category` VALUES ('3', '文具用品');
INSERT INTO `t_category` VALUES ('4', '休闲食品');-- ----------------------------
-- Table structure for `t_order`
-- ----------------------------
DROP TABLE IF EXISTS `t_order`;
CREATE TABLE `t_order` (`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '订单标识符',`username` varchar(20) DEFAULT NULL COMMENT '用户名',`telephone` varchar(11) DEFAULT NULL COMMENT '电话号码',`total_price` double DEFAULT NULL COMMENT '总金额',`delivery_address` varchar(50) DEFAULT NULL COMMENT '送货地址',`order_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP COMMENT '下单时间',PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8;-- ----------------------------
-- Records of t_order
-- ----------------------------
INSERT INTO `t_order` VALUES ('1', '郑晓红', '13956567889', '2000', '泸职院信息工程系', '2016-12-25 17:12:36');
INSERT INTO `t_order` VALUES ('2', '温志军', '13956678907', '1000', '泸职院机械工程系', '2016-12-02 17:12:17');-- ----------------------------
-- Table structure for `t_product`
-- ----------------------------
DROP TABLE IF EXISTS `t_product`;
CREATE TABLE `t_product` (`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '商品标识符',`name` varchar(200) NOT NULL COMMENT '商品名称',`price` double DEFAULT NULL COMMENT '商品单价',`add_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,`category_id` int(11) DEFAULT NULL COMMENT '商品类别标识符',PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=16 DEFAULT CHARSET=utf8;-- ----------------------------
-- Records of t_product
-- ----------------------------
INSERT INTO `t_product` VALUES ('1', '容声电冰箱', '2000', '2016-12-20 09:54:41', '1');
INSERT INTO `t_product` VALUES ('2', '松下电视', '5000', '2016-12-20 09:54:35', '1');
INSERT INTO `t_product` VALUES ('3', '红岩墨水', '3', '2016-12-20 09:56:05', '3');
INSERT INTO `t_product` VALUES ('4', '海尔洗衣机', '1000', '2016-11-30 08:58:09', '1');
INSERT INTO `t_product` VALUES ('5', '新宇电饭煲', '1200', '2016-12-20 09:55:11', '1');
INSERT INTO `t_product` VALUES ('6', '英雄微波炉', '600', '2016-12-20 09:55:39', '1');
INSERT INTO `t_product` VALUES ('7', '红双喜席梦思', '700', '2016-11-28 08:59:38', '2');
INSERT INTO `t_product` VALUES ('8', '旺仔牛奶糖', '24.4', '2016-12-20 10:00:11', '4');
INSERT INTO `t_product` VALUES ('9', '西蒙枕头', '100', '2016-12-20 09:56:57', '2');
INSERT INTO `t_product` VALUES ('10', '甜甜毛毯', '400', '2016-12-20 09:57:26', '2');
INSERT INTO `t_product` VALUES ('11', '永久钢笔', '50', '2016-12-20 09:57:30', '3');
INSERT INTO `t_product` VALUES ('12', '硬面抄笔记本', '5', '2016-12-20 09:57:53', '3');
INSERT INTO `t_product` VALUES ('13', '晨光橡皮擦', '0.5', '2016-11-30 09:02:40', '3');
INSERT INTO `t_product` VALUES ('14', '美的空调', '3000', '2016-11-03 09:03:02', '1');
INSERT INTO `t_product` VALUES ('15', '迷你深海鱼肠', '14.4', '2016-12-02 10:01:14', '4');-- ----------------------------
-- Table structure for `t_user`
-- ----------------------------
DROP TABLE IF EXISTS `t_user`;
CREATE TABLE `t_user` (`id` int(11) NOT NULL AUTO_INCREMENT,`username` varchar(20) NOT NULL,`password` varchar(20) DEFAULT NULL,`telephone` varchar(11) DEFAULT NULL,`register_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,`popedom` int(11) DEFAULT NULL COMMENT '0：管理员；1：普通用户',PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;-- ----------------------------
-- Records of t_user
-- ----------------------------
INSERT INTO `t_user` VALUES ('1', 'admin', '12345', '15734345678', '2016-12-02 08:40:35', '0');
INSERT INTO `t_user` VALUES ('2', '郑晓红', '11111', '13956567889', '2016-12-20 09:51:43', '1');
INSERT INTO `t_user` VALUES ('3', '温志军', '22222', '13956678907', '2016-12-20 09:52:36', '1');
INSERT INTO `t_user` VALUES ('4', '涂文艳', '33333', '15890905678', '2016-12-05 09:52:56', '1');

四、项目结构图

五、系统实现

（一）实体类（net.wlq.shop.bean）

1、用户实体（User）

package net.wlq.shop.bean;/*** 功能：用户实体类* 作者：wlq* 日期：2019年12月2日*/import java.util.Date;public class User {/*** 用户标识符*/private int id;/*** 用户名*/private String username;/*** 密码*/private String password;/*** 电话号码*/private String telephone;/*** 注册时间*/private Date registerTime;/*** 权限（0：管理员；1：普通用户）*/private int popedom;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public String getTelephone() {return telephone;}public void setTelephone(String telephone) {this.telephone = telephone;}public Date getRegisterTime() {return registerTime;}public void setRegisterTime(Date registerTime) {this.registerTime = registerTime;}public int getPopedom() {return popedom;}public void setPopedom(int popedom) {this.popedom = popedom;}@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +", telephone='" + telephone + '\'' +", registerTime=" + registerTime +", popedom=" + popedom +'}';}
}

2、类别实体（Category）

package net.wlq.shop.bean;/*** 功能：商品类别实体类* 作者：wlq* 日期：2019年12月2日*/public class Cotegory {/*** 类别标识符*/private int id;/*** 类别名称*/private String name;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}@Overridepublic String toString() {return "Category{" +"id=" + id +", name='" + name + '\'' +'}';}
}

3、商品实体（Product）

package net.wlq.shop.bean;/*** 功能：商品实体类* 作者：wlq* 日期：2019年12月2日*/import java.util.Date;public class Product {/*** 商品标识符*/private int id;/*** 商品名称*/private String name;/*** 商品单价*/private double price;/*** 商品上架时间*/private Date addTime;/*** 商品所属类别标识符*/private int categoryId;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public double getPrice() {return price;}public void setPrice(double price) {this.price = price;}public Date getAddTime() {return addTime;}public void setAddTime(Date addTime) {this.addTime = addTime;}public int getCategoryId() {return categoryId;}public void setCategoryId(int categoryId) {this.categoryId = categoryId;}@Overridepublic String toString() {return "Product{" +"id=" + id +", name='" + name + '\'' +", price=" + price +", addTime=" + addTime +", categoryId=" + categoryId +'}';}
}

4、订单实体（Order）

package net.wlq.shop.bean;/*** 功能：订单实体类* 作者：wlq* 日期：2019年12月2日*/import java.util.Date;public class Order {/*** 订单标识符*/private int id;/*** 用户名*/private String username;/*** 联系电话*/private String telephone;/*** 订单总金额*/private double totalPrice;/*** 送货地址*/private String deliveryAddress;/*** 下单时间*/private Date orderTime;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getTelephone() {return telephone;}public void setTelephone(String telephone) {this.telephone = telephone;}public double getTotalPrice() {return totalPrice;}public void setTotalPrice(double totalPrice) {this.totalPrice = totalPrice;}public String getDeliveryAddress() {return deliveryAddress;}public void setDeliveryAddress(String deliveryAddress) {this.deliveryAddress = deliveryAddress;}public Date getOrderTime() {return orderTime;}public void setOrderTime(Date orderTime) {this.orderTime = orderTime;}@Overridepublic String toString() {return "Order{" +"id=" + id +", username='" + username + '\'' +", telephone='" + telephone + '\'' +", totalPrice=" + totalPrice +", deliveryAddress='" + deliveryAddress + '\'' +", orderTime=" + orderTime +'}';}
}

（二）数据库工具类（net.wlq.shop.dbutil）

1 ，需要先在WEB-INF目录下创建lib子目录，添加MySQL驱动程序jar包

需要的可以找我！！！！！！！！

2,创建数据库连接管理类ConnectionManager

package net.wlq.shop.dbutil;/*** 功能：数据库连接管理类* 作者：wlq* 日期：2019年12月2日*/import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;import javax.swing.JOptionPane;public class ConnectionManager {/*** 数据库驱动程序*/private static final String DRIVER = "com.mysql.jdbc.Driver";/*** 数据库统一资源标识符*/private static final String URL = "jdbc:mysql://localhost:3306/simonshop";/*** 数据库用户名*/private static final String USERNAME = "root";/*** 数据库密码*/private static final String PASSWORD = "18205071";/*** 私有化构造方法，拒绝实例化*/private ConnectionManager() {}/*** 获得数据库连接** @return 数据库连接对象*/public static Connection getConnection() {// 定义数据库连接Connection conn = null;try {// 安装数据库驱动程序Class.forName(DRIVER);// 获得数据库连接conn = DriverManager.getConnection(URL+ "?useUnicode=true&characterEncoding=UTF8", USERNAME, PASSWORD);} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}// 返回数据库连接return conn;}/*** 关闭数据库连接** @param conn*/public static void closeConnection(Connection conn) {// 判断数据库连接是否为空if (conn != null) {// 判断数据库连接是否关闭try {if (!conn.isClosed()) {// 关闭数据库连接conn.close();}} catch (SQLException e) {e.printStackTrace();}}}/*** 测试数据库连接是否成功** @param args*/public static void main(String[] args) {// 获得数据库连接Connection conn = getConnection();// 判断是否连接成功if (conn != null) {JOptionPane.showMessageDialog(null, "恭喜，数据库连接成功！");} else {JOptionPane.showMessageDialog(null, "遗憾，数据库连接失败！");}// 关闭数据库连接closeConnection(conn);}
}

我们可以来运行一下，看数据库是否连接成功：

（三）数据访问层接口（XXXDao）

在src里创建net.wlq.shop.dao包，在里面创建UserDao，CategoryDao，ProductDao，OrderDao

1、用户数据访问接口（UserDao）

package net.wlq.shop.dao;/*** 功能：用户数据访问接口* 作者：wlq* 日期：2019年12月2日*/import java.util.List;import net.wlq.shop.bean.User;public interface UserDao {// 插入用户int insert(User user);// 按标识符删除用户int deleteById(int id);// 更新用户int update(User user);// 按标识符查询用户User findById(int id);// 按用户名查询用户List<User> findByUsername(String username);// 查询全部用户List<User> findAll();// 用户登录User login(String username, String password);
}

2、类别数据访问接口（CategoryDao）

package net.wlq.shop.dao;
/*** 功能：类别数据访问接口* 作者：wlq* 日期：2019年12月10日*/import java.util.List;import net.wlq.shop.bean.Category;public interface CategoryDao {// 插入类别int insert(Category category);// 按标识符删除类别int deleteById(int id);// 更新类别int update(Category category);// 按标识符查询类别Category findById(int id);// 查询全部类别List<Category> findAll();
}

3、商品数据访问接口（ProductDao）

package net.wlq.shop.dao;
/*** 功能：商品数据访问接口* 作者：wlq* 日期：2019年12月16日*/import java.util.List;import net.wlq.shop.bean.Product;public interface ProductDao {// 插入商品int insert(Product product);// 按标识符删除商品int deleteById(int id);// 更新商品int update(Product product);// 按标识符查询商品Product findById(int id);// 按类别查询商品List<Product> findByCategoryId(int categoryId);// 查询全部商品List<Product> findAll();
}

4、订单数据访问接口（OrderDao）

package net.wlq.shop.dao;/*** 功能：订单数据访问接口* 作者：wlq* 日期：2019年12月25日*/import java.util.List;import net.wlq.shop.bean.Order;public interface OrderDao {// 插入订单int insert(Order order);// 按标识符删除订单int deleteById(int id);// 更新订单int update(Order order);// 按标识符查询订单Order findById(int id);// 查询最后一个订单Order findLast();// 查询全部订单List<Order> findAll();
}

（四）数据访问层实现类（XXXDaoImpl）

在src创建net.wlq.shop.dao.impl包，在里面创建UserImpl，CategoryDaoImpl，ProductDaoImpl，OrderDaoImpl

1、用户数据访问接口实现类（UserDaoImpl）

package net.wlq.shop.dao.impl;/*** 功能：用户数据访问接口实现类* 作者：wlq* 日期：2019年12月2日*/import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;import net.wlq.shop.bean.Category;
import net.wlq.shop.bean.User;
import net.wlq.shop.dao.UserDao;
import net.wlq.shop.dbutil.ConnectionManager;public class UserDaoImpl implements UserDao {/*** 插入用户*/@Overridepublic int insert(User user) {// 定义插入记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "INSERT INTO t_user (username, password, telephone, register_time, popedom)"+ " VALUES (?, ?, ?, ?, ?)";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, user.getUsername());pstmt.setString(2, user.getPassword());pstmt.setString(3, user.getTelephone());pstmt.setTimestamp(4, new Timestamp(user.getRegisterTime().getTime()));pstmt.setInt(5, user.getPopedom());// 执行更新操作，插入新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回插入记录数return count;}/*** 删除用户记录*/@Overridepublic int deleteById(int id) {// 定义删除记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "DELETE FROM t_user WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行更新操作，删除记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回删除记录数return count;}/*** 更新用户*/@Overridepublic int update(User user) {// 定义更新记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "UPDATE t_user SET username = ?, password = ?, telephone = ?,"+ " register_time = ?, popedom = ? WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, user.getUsername());pstmt.setString(2, user.getPassword());pstmt.setString(3, user.getTelephone());pstmt.setTimestamp(4, new Timestamp(user.getRegisterTime().getTime()));pstmt.setInt(5, user.getPopedom());pstmt.setInt(6, user.getId());// 执行更新操作，更新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回更新记录数return count;}/*** 按标识符查询用户*/@Overridepublic User findById(int id) {// 声明用户User user = null;// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_user WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行SQL查询，返回结果集ResultSet rs = pstmt.executeQuery();// 判断结果集是否有记录if (rs.next()) {// 实例化用户user = new User();// 利用当前记录字段值去设置商品类别的属性user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));user.setTelephone(rs.getString("telephone"));user.setRegisterTime(rs.getTimestamp("register_time"));user.setPopedom(rs.getInt("popedom"));}} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回用户return user;}@Overridepublic List<User> findByUsername(String username) {// 声明用户列表List<User> users = new ArrayList<User>();// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_user WHERE username = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, username);// 执行SQL查询，返回结果集ResultSet rs = pstmt.executeQuery();// 遍历结果集while (rs.next()) {// 创建类别实体User user = new User();// 设置实体属性user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));user.setTelephone(rs.getString("telephone"));user.setRegisterTime(rs.getTimestamp("register_time"));user.setPopedom(rs.getInt("popedom"));// 将实体添加到用户列表users.add(user);}// 关闭结果集rs.close();// 关闭语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回用户列表return users;}@Overridepublic List<User> findAll() {// 声明用户列表List<User> users = new ArrayList<User>();// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_user";try {// 创建语句对象Statement stmt = conn.createStatement();// 执行SQL，返回结果集ResultSet rs = stmt.executeQuery(strSQL);// 遍历结果集while (rs.next()) {// 创建用户实体User user = new User();// 设置实体属性user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));user.setTelephone(rs.getString("telephone"));user.setRegisterTime(rs.getTimestamp("register_time"));user.setPopedom(rs.getInt("popedom"));// 将实体添加到用户列表users.add(user);}// 关闭结果集rs.close();// 关闭语句对象stmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回用户列表return users;}/*** 登录方法*/@Overridepublic User login(String username, String password) {// 定义用户对象User user = null;// 获取数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_user WHERE username = ? AND password = ?";try {// 创建预备语句对象PreparedStatement psmt = conn.prepareStatement(strSQL);// 设置占位符的值psmt.setString(1, username);psmt.setString(2, password);// 执行查询，返回结果集ResultSet rs = psmt.executeQuery();// 判断结果集是否有记录if (rs.next()) {// 实例化用户对象user = new User();// 用记录值设置用户属性user.setId(rs.getInt("id"));user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));user.setTelephone(rs.getString("telephone"));user.setRegisterTime(rs.getDate("register_time"));user.setPopedom(rs.getInt("popedom"));}// 关闭结果集rs.close();// 关闭预备语句psmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回用户对象return user;}
}

2、类别数据访问接口实现类（CategoryDaoImpl）

package net.wlq.shop.dao.impl;/*** 功能：类别数据访问接口实现类* 作者：wlq* 日期：2019年12月10日*/import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;import net.wlq.shop.bean.Category;
import net.wlq.shop.dao.CategoryDao;
import net.wlq.shop.dbutil.ConnectionManager;public class CategoryDaoImpl implements CategoryDao {/*** 插入类别*/@Overridepublic int insert(Category category) {// 定义插入记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "INSERT INTO t_category (name) VALUES (?)";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, category.getName());// 执行更新操作，插入新录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回插入记录数return count;}/*** 删除类别*/@Overridepublic int deleteById(int id) {// 定义删除记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "DELETE FROM t_category WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行更新操作，删除记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回删除记录数return count;}/*** 更新类别*/@Overridepublic int update(Category category) {// 定义更新记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "UPDATE t_category SET name = ? WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, category.getName());pstmt.setInt(2, category.getId());// 执行更新操作，更新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回更新记录数return count;}/*** 按标识符查询类别*/@Overridepublic Category findById(int id) {// 声明商品类别Category category = null;// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_category WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行SQL查询，返回结果集ResultSet rs = pstmt.executeQuery();// 判断结果集是否有记录if (rs.next()) {// 实例化商品类别category = new Category();// 利用当前记录字段值去设置商品类别的属性category.setId(rs.getInt("id"));category.setName(rs.getString("name"));}} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回商品类别return category;}/*** 查询全部类别*/@Overridepublic List<Category> findAll() {// 声明类别列表List<Category> categories = new ArrayList<Category>();// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_category";try {// 创建语句对象Statement stmt = conn.createStatement();// 执行SQL，返回结果集ResultSet rs = stmt.executeQuery(strSQL);// 遍历结果集while (rs.next()) {// 创建类别实体Category category = new Category();// 设置实体属性category.setId(rs.getInt("id"));category.setName(rs.getString("name"));// 将实体添加到类别列表categories.add(category);}// 关闭结果集rs.close();// 关闭语句对象stmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回类别列表return categories;}
}

3、商品数据访问接口实现类（ProductDaoImpl）

package net.wlq.shop.dao.impl;/*** 功能：产品数据访问接口实现类* 作者：华卫* 日期：2016年12月16日*/import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;import net.wlq.shop.bean.Product;
import net.wlq.shop.bean.User;
import net.wlq.shop.dao.ProductDao;
import net.wlq.shop.dbutil.ConnectionManager;public class ProductDaoImpl implements ProductDao {/*** 插入商品*/@Overridepublic int insert(Product product) {// 定义插入记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "INSERT INTO t_product (name, price, add_time, category_id)" + " VALUES (?, ?, ?, ?)";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, product.getName());pstmt.setDouble(2, product.getPrice());pstmt.setTimestamp(3, new Timestamp(product.getAddTime().getTime()));pstmt.setInt(4, product.getCategoryId());// 执行更新操作，插入新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回插入记录数return count;}/*** 删除商品*/@Overridepublic int deleteById(int id) {// 定义删除记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "DELETE FROM t_product WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行更新操作，删除记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回删除记录数return count;}/*** 更新商品*/@Overridepublic int update(Product product) {// 定义更新记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "UPDATE t_product SET name = ?, price = ?, add_time = ?,"+ " category_id = ? WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, product.getName());pstmt.setDouble(2, product.getPrice());pstmt.setTimestamp(3, new Timestamp(product.getAddTime().getTime()));pstmt.setInt(4, product.getCategoryId());pstmt.setInt(5, product.getId());// 执行更新操作，更新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回更新记录数return count;}/*** 按标识符查找商品*/@Overridepublic Product findById(int id) {// 声明商品Product product = null;// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_product WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行SQL查询，返回结果集ResultSet rs = pstmt.executeQuery();// 判断结果集是否有记录if (rs.next()) {// 实例化商品product = new Product();// 利用当前记录字段值去设置商品类别的属性product.setId(rs.getInt("id"));product.setName(rs.getString("name"));product.setPrice(rs.getDouble("price"));product.setAddTime(rs.getTimestamp("add_time"));product.setCategoryId(rs.getInt("category_id"));}} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回商品return product;}/*** 按类别查询商品*/@Overridepublic List<Product> findByCategoryId(int categoryId) {// 定义商品列表List<Product> products = new ArrayList<Product>();// 获取数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_product WHERE category_id = ?";try {// 创建预备语句PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, categoryId);// 执行SQL语句，返回结果集ResultSet rs = pstmt.executeQuery();// 遍历结果集，将其中的每条记录生成商品对象，添加到商品列表while (rs.next()) {// 实例化商品对象Product product = new Product();// 利用当前记录字段值设置实体对应属性product.setId(rs.getInt("id"));product.setName(rs.getString("name"));product.setPrice(rs.getDouble("price"));product.setAddTime(rs.getTimestamp("add_time"));product.setCategoryId(rs.getInt("category_id"));// 将商品添加到商品列表products.add(product);}} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回商品列表return products;}/*** 查询全部商品*/@Overridepublic List<Product> findAll() {// 声明商品列表List<Product> products = new ArrayList<Product>();// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_product";try {// 创建语句对象Statement stmt = conn.createStatement();// 执行SQL，返回结果集ResultSet rs = stmt.executeQuery(strSQL);// 遍历结果集while (rs.next()) {// 创建商品实体Product product = new Product();// 设置实体属性product.setId(rs.getInt("id"));product.setName(rs.getString("name"));product.setPrice(rs.getDouble("price"));product.setAddTime(rs.getTimestamp("add_time"));product.setCategoryId(rs.getInt("category_id"));// 将实体添加到商品列表products.add(product);}// 关闭结果集rs.close();// 关闭语句对象stmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回商品列表return products;}
}

4、订单数据访问接口实现类（OrderDaoImpl）

package net.wlq.shop.dao.impl;/*** 功能：订单数据访问接口实现类* 作者：wlq* 日期：2019年12月25日*/import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;import net.wlq.shop.bean.Category;
import net.wlq.shop.bean.Order;
import net.wlq.shop.bean.User;
import net.wlq.shop.dao.OrderDao;
import net.wlq.shop.dbutil.ConnectionManager;public class OrderDaoImpl implements OrderDao {/*** 插入订单*/@Overridepublic int insert(Order order) {// 定义插入记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "INSERT INTO t_order (username, telephone, total_price, delivery_address, order_time)"+ " VALUES (?, ?, ?, ?, ?)";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, order.getUsername());pstmt.setString(2, order.getTelephone());pstmt.setDouble(3, order.getTotalPrice());pstmt.setString(4, order.getDeliveryAddress());pstmt.setTimestamp(5, new Timestamp(order.getOrderTime().getTime()));// 执行更新操作，插入记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回插入记录数return count;}/*** 删除订单*/@Overridepublic int deleteById(int id) {// 定义删除记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "DELETE FROM t_order WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行更新操作，删除记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回删除记录数return count;}/*** 更新订单*/@Overridepublic int update(Order order) {// 定义更新记录数int count = 0;// 获得数据库连接Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "UPDATE t_order SET username = ?, telephone = ?, total_price = ?,"+ " delivery_address = ?, order_time = ? WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setString(1, order.getUsername());pstmt.setString(2, order.getTelephone());pstmt.setDouble(3, order.getTotalPrice());pstmt.setString(4, order.getDeliveryAddress());pstmt.setTimestamp(5, new Timestamp(order.getOrderTime().getTime()));pstmt.setInt(6, order.getId());// 执行更新操作，更新记录count = pstmt.executeUpdate();// 关闭预备语句对象pstmt.close();} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回更新记录数return count;}/*** 查询最后一个订单*/@Overridepublic Order findLast() {// 声明订单Order order = null;// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_order";try {// 创建语句对象Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);// 执行SQL，返回结果集ResultSet rs = stmt.executeQuery(strSQL);// 定位到最后一条记录if (rs.last()) {// 创建订单实体order = new Order();// 设置实体属性order.setId(rs.getInt("id"));order.setUsername(rs.getString("username"));order.setTelephone(rs.getString("telephone"));order.setTotalPrice(rs.getDouble("total_price"));order.setDeliveryAddress(rs.getString("delivery_address"));order.setOrderTime(rs.getTimestamp("order_time"));}// 关闭结果集rs.close();// 关闭语句对象stmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回订单对象return order;}/*** 按标识符查询订单*/@Overridepublic Order findById(int id) {// 声明订单Order order = null;// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_order WHERE id = ?";try {// 创建预备语句对象PreparedStatement pstmt = conn.prepareStatement(strSQL);// 设置占位符的值pstmt.setInt(1, id);// 执行SQL查询，返回结果集ResultSet rs = pstmt.executeQuery();// 判断结果集是否有记录if (rs.next()) {// 实例化订单order = new Order();// 利用当前记录字段值去设置订单的属性order.setId(rs.getInt("id"));order.setUsername(rs.getString("username"));order.setTelephone(rs.getString("telephone"));order.setDeliveryAddress(rs.getString("delivery_address"));order.setOrderTime(rs.getTimestamp("order_time"));}} catch (SQLException e) {e.printStackTrace();} finally {ConnectionManager.closeConnection(conn);}// 返回订单return order;}/*** 查询全部订单*/@Overridepublic List<Order> findAll() {// 声明订单列表List<Order> orders = new ArrayList<Order>();// 获取数据库连接对象Connection conn = ConnectionManager.getConnection();// 定义SQL字符串String strSQL = "SELECT * FROM t_order";try {// 创建语句对象Statement stmt = conn.createStatement();// 执行SQL，返回结果集ResultSet rs = stmt.executeQuery(strSQL);// 遍历结果集while (rs.next()) {// 创建订单实体Order order = new Order();// 设置实体属性order.setId(rs.getInt("id"));order.setUsername(rs.getString("username"));order.setTelephone(rs.getString("telephone"));order.setDeliveryAddress(rs.getString("delivery_address"));order.setOrderTime(rs.getTimestamp("order_time"));// 将实体添加到订单列表orders.add(order);}// 关闭结果集rs.close();// 关闭语句对象stmt.close();} catch (SQLException e) {e.printStackTrace();} finally {// 关闭数据库连接ConnectionManager.closeConnection(conn);}// 返回用户列表return orders;}
}

5，我们需要对用户数据访问接口实现类的各个方法进行单元测试，采用JUnit来进行单元测试

在项目根目录创建一个test文件夹，然后在项目结构窗口里选择Modules里的sources如下图选择Test

由灰色改为绿色，即是测试

在test文件夹里创建net.wlq.shop.dao.impl包，在里面创建测试类TestUserDaoImpl：
（1）在TestUserDaoImpl类里面编写测试方法testLogin()

TestUserDaoImpl代码：

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.User;
import net.wlq.shop.dao.UserDao;
import org.junit.Test;import java.util.Scanner;public class TestUserDaoImpl {@Testpublic void testLogin(){//输入用户名和密码String username,password;Scanner sc = new Scanner(System.in);username = "admin";password= "12345";//父接口指向子类对象UserDao userDao = new UserDaoImpl();User user =userDao.login(username,password);//判断用户登录是否成功if (user != null) {System.out.println("恭喜，登录成功！");}else {System.out.println("遗憾，登录失败！");}}
}

（1）运行单元测试方法testLogin()：

（2）编写测试方法testUpdate()

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.User;
import net.wlq.shop.dao.UserDao;
import org.junit.Test;import java.util.Date;
import java.util.List;
import java.util.Scanner;public class TestUserDaoImpl {@Testpublic void testLogin(){//输入用户名和密码String username,password;Scanner sc = new Scanner(System.in);username = "admin";password= "12345";//父接口指向子类对象UserDao userDao = new UserDaoImpl();User user =userDao.login(username,password);//判断用户登录是否成功if (user != null) {System.out.println("恭喜，登录成功！");}else {System.out.println("遗憾，登录失败！");}}@Testpublic void testUpdate(){//将用户【涂文艳】的密码改为121212,//定义用户数据访问接口UserDao userDao = new UserDaoImpl();//找到用户，其id是4User user = userDao.findById(4);//修改其密码与电话号码user.setPassword("121212");user.setTelephone("14253738292");int count = userDao.update(user);if (count >0) {System.out.println("恭喜，记录更新成功！");}else {System.out.println("遗憾，记录登录失败！");}user  =userDao.findById(4);System.out.println(user);}//按标识符查询用户@Testpublic void testFindById(){//定义用户数据访问接口UserDao userDao = new UserDaoImpl();User user = userDao.findById(1);int count = userDao.update(user);if (count >0) {System.out.println("恭喜，查询成功！");}else {System.out.println("遗憾，查询失败！");}System.out.println(user);}/*** 测试访问全部用户* */@Testpublic  void testfindAll(){//定义用户数据访问接口UserDao userDao = new UserDaoImpl();List<User> users = userDao.findAll();for (User user:users) {System.out.println(user);}}/*** 删除指定用户** */@Testpublic  void  testDeleteUser(){//定义用户数据访问接口UserDao userDao = new UserDaoImpl();int id =1;int count = userDao.deleteById(id);if (count >0) {System.out.println("恭喜，删除成功！");}else {System.out.println("遗憾，删除失败！");}}@Testpublic void testInsert(){User user = new User();user.setId(2);user.setPassword("121212");user.setUsername("郑晓红");user.setTelephone("15284923627");user.setRegisterTime(new Date());//定义用户数据访问接口UserDao userDao = new UserDaoImpl();int count = userDao.insert(user);if (count > 0) {System.out.println("恭喜，用户记录插入成功！");}else {System.out.println("遗憾，用户记录插入失败！");}}}

运行结果：

上面代码还有其他测试方法，可以自己运行看一下！！！！！！！！！

(3)编写TestCategoryDaoImpl测试类

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.Category;
import net.wlq.shop.dao.CategoryDao;
import org.junit.Test;import java.util.List;public class TestCategoryDaoImpl {@Testpublic void testFindAll(){CategoryDao categoryDao = new CategoryDaoImpl();List<Category> categories = categoryDao.findAll();if (categories.size()>0) {for (Category category:categories) {System.out.println(category);}}else {System.out.println("没有商品类别！");}}
}

运行结果如下：

(4)编写测试方法TestProductDaoImpl类，编写测试方法 testFindByCategoryId()：

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.Product;
import net.wlq.shop.dao.CategoryDao;
import net.wlq.shop.dao.ProductDao;
import org.junit.Test;import java.sql.PreparedStatement;
import java.util.List;public class TestProductDaoImpl {@Testpublic  void  testFindByCategoryId(){ProductDao productDao = new ProductDaoImpl();int categoryId = 1;CategoryDao categoryDao = new CategoryDaoImpl();String categoryName = categoryDao.findById(categoryId).getName();List<Product> products = productDao.findByCategoryId(categoryId);if (!products.isEmpty()) {for (Product product:products) {System.out.println(product);}}else {System.out.println("["+categoryName+"]没有类似的商品！");}}
}

我们可以修改商品id，再次查询商品：
当categoryId= 5，代码运行会报空指针异常！

这时我们需要修改一下代码：

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.Product;
import net.wlq.shop.dao.CategoryDao;
import net.wlq.shop.dao.ProductDao;
import org.junit.Test;import java.sql.PreparedStatement;
import java.util.List;public class TestProductDaoImpl {@Testpublic  void  testFindByCategoryId(){ProductDao productDao = new ProductDaoImpl();int categoryId = 5;CategoryDao categoryDao = new CategoryDaoImpl();if (categoryDao.findById(categoryId) != null){String categoryName = categoryDao.findById(categoryId).getName();List<Product> products = productDao.findByCategoryId(categoryId);if (products.isEmpty()) {for (Product product:products) {System.out.println(product);}}else {System.out.println("["+categoryName+"]没有类似的商品！");}}else {System.out.println("类别编号[" + categoryId + "]不存在！");}}}

这时运行的代码如下：

（5）创建测试类TestOrderDaoImpl，编写测试方法testFindAll()

package net.wlq.shop.dao.impl;import net.wlq.shop.bean.Order;
import net.wlq.shop.dao.OrderDao;
import org.junit.Test;import java.util.List;public class TestOrderDaoImpl {@Testpublic  void  testFindAll(){OrderDao orderDao = new OrderDaoImpl();List<Order> orders = orderDao.findAll();if (orders.size() > 0) {for (Order order: orders) {System.out.println(order);}}else {System.out.println("没有订单！");}}
}

（五）数据服务层接口（XXXService）

在src里创建net.wlq.shop.service包，在里面创建4个服务接口
1、用户服务接口（UserService）

package net.wlq.shop.service;/*** 功能：用户服务类* 作者：wlq* 日期：2019年12月2日*/import java.util.List;import net.wlq.shop.bean.User;import net.wlq.shop.dao.UserDao;import net.wlq.shop.dao.impl.UserDaoImpl;public class UserService {/*** 声明用户访问对象*/private UserDao userDao = new UserDaoImpl();public int addUser(User user) {return userDao.insert(user);}public int deleteUserById(int id) {return userDao.deleteById(id);}public int updateUser(User user) {return userDao.update(user);}public User findUserById(int id) {return userDao.findById(id);}public List<User> findUsersByUsername(String username) {return userDao.findByUsername(username);}public List<User> findAllUsers() {return userDao.findAll();}public User login(String username, String password) {return userDao.login(username, password);}
}

2、类别服务接口（CategoryService）

package net.wlq.shop.service;/*** 功能：类别服务类* 作者：wlq* 日期：2019年12月10日*/import java.util.List;import net.wlq.shop.bean.Category;
import net.wlq.shop.dao.CategoryDao;
import net.wlq.shop.dao.impl.CategoryDaoImpl;public class CategoryService {/*** 声明类别数据访问对象*/private CategoryDao categoryDao = new CategoryDaoImpl();public int addCategory(Category category) {return categoryDao.insert(category);}public int deleteCategoryById(int id) {return categoryDao.deleteById(id);}public int updateCategory(Category category) {return categoryDao.update(category);}public Category findCategoryById(int id) {return categoryDao.findById(id);}public List<Category> findAllCategories() {return categoryDao.findAll();}
}

3、商品服务接口（ProductService）

package net.wlq.shop.service;/*** 功能：商品服务类* 作者：wlq* 日期：2019年12月16日*/import java.util.List;import net.wlq.shop.bean.Product;
import net.wlq.shop.dao.ProductDao;
import net.wlq.shop.dao.impl.ProductDaoImpl;public class ProductService {/*** 声明商品数据访问对象*/private ProductDao productDao = new ProductDaoImpl();public int addProduct(Product product) {return productDao.insert(product);}public int deleteProductById(int id) {return productDao.deleteById(id);}public int updateProduct(Product product) {return productDao.update(product);}public Product findProductById(int id) {return productDao.findById(id);}public List<Product> findProductsByCategoryId(int categoryId) {return productDao.findByCategoryId(categoryId);}public List<Product> findAllProducts() {return productDao.findAll();}
}

4、订单服务接口（OrderService）

package net.wlq.shop.service;/*** 功能：订单服务实现类* 作者：wlq* 日期：2019年12月19日*/import java.util.List;import net.wlq.shop.bean.Order;
import net.wlq.shop.dao.OrderDao;
import net.wlq.shop.dao.impl.OrderDaoImpl;public class OrderService {/*** 声明订单数据访问对象*/OrderDao orderDao = new OrderDaoImpl();public int addOrder(Order order) {return orderDao.insert(order);}public int deleteOrderById(int id) {return orderDao.deleteById(id);}public int updateOrder(Order order) {return orderDao.update(order);}public Order findOrderById(int id) {return orderDao.findById(id);}public Order findLastOrder() {return orderDao.findLast();}public List<Order> findAllOrders() {return orderDao.findAll();}
}

课堂练习：创建四个测试类：TestUserService，TestCategoryService，TestProductService，TestOderService

下面是查找全部用户的结果：

输出内容忘记修改，应该是类别实体删除失败！

（六）控制层（Servlet）

1、登录处理类（LoginServlet）

package net.wlq.shop.servlet;/*** 功能：登录处理类* 作者：wlq* 日期：2019年12月9日*/import java.io.IOException;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 net.wlq.shop.bean.User;
import net.wlq.shop.service.UserService;@WebServlet("/login")
public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 设置请求对象的字符编码request.setCharacterEncoding("utf-8");// 获取会话对象HttpSession session = request.getSession();// 获取用户名String username = request.getParameter("username");// 获取密码String password = request.getParameter("password");// 定义用户服务对象UserService userService = new UserService(); //这里是修改了的// 执行登录方法，返回用户实体User user = userService.login(username, password);// 判断用户登录是否成功if (user != null) {// 设置session属性session.setMaxInactiveInterval(5 * 60);session.setAttribute("username", username);session.removeAttribute("loginMsg");// 根据用户权限跳转到不同页面if (user.getPopedom() == 0) {response.sendRedirect(request.getContextPath() + "/backend/management.jsp");} else if (user.getPopedom() == 1) {response.sendRedirect(request.getContextPath() + "/showCategory");}} else {// 设置session属性loginMsgsession.setAttribute("loginMsg", "用户名或密码错误！");response.sendRedirect(request.getContextPath() + "/login.jsp");}}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

下面我们来进行测试，测试之前我们来修改一下首页index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html><head><title>index</title></head><body><h3>欢迎来到西蒙购物网</h3></body>
</html>

测试结果截图：

(1),启动服务器，来到indx.jsp页面，显示如下

在地址栏里localhost:8080之后输入lojin?username=用户名&password=密码,进行跳转会报404错误，因为没有lojin.jsp页面

在这里我们输入正确的用户名和密码

再回到服务器的控制台，查看结果为：

这就说明我们的代码运行成功，可以进入到login.jsp页面，下面我们可以测试一下当用户名输入错误或者密码错误时的结果

(2),重启服务器，再次测试：

在地址栏里故意写错密码，回到控制台查看显示结果：

(3),再次重启服务器，查看结果:

在地址栏里，故意将用户名写错，再回到控制台查看结果：

2、注销处理类（LogoutServlet）

package net.wlq.shop.servlet;/*** 功能：注销处理类* 作者：wlq* 日期：2019年12月9日*/import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;@WebServlet("/logout")
public class LogoutServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 让session失效request.getSession().invalidate();// 重定向到登录页面response.sendRedirect(request.getContextPath() + "/login.jsp");System.out.println("用户注销成功1");}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

下面我们来进行测试：

测试结果截图：

启动服务器，先要登录成功，然后在测试注销功能。

这里因为没写页面，所以会报404错误

3、注册处理类（RegisterServlet）

package net.wlq.shop.servlet;/*** 功能：处理用户注册* 作者：wlq* 日期：2019年12月9日*/import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLEncoder;
import java.sql.Timestamp;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 net.wlq.shop.bean.User;
import net.wlq.shop.service.UserService;@WebServlet("/register")
public class RegisterServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 设置请求对象的字符编码request.setCharacterEncoding("utf-8");// 获取session对象HttpSession session = request.getSession();// 获取用户名String username = request.getParameter("username");// 获取密码String password = request.getParameter("password");// 获取电话号码String telephone = request.getParameter("telephone");// 设置注册时间（时间戳对象）Timestamp registerTime = new Timestamp(System.currentTimeMillis());// 设置用户为普通用户int popedom = 1;// 创建用户对象User user = new User();// 设置用户对象信息user.setUsername(username);user.setPassword(password);user.setTelephone(telephone);user.setRegisterTime(registerTime);user.setPopedom(popedom);// 创建UserService对象UserService userService = new UserService();// 调用UserService对象的添加用户方法int count = userService.addUser(user);// 判断是否注册成功if (count > 0) {// 设置session属性session.setAttribute("registerMsg", "恭喜，注册成功！");// 重定向到登录页面response.sendRedirect(request.getContextPath() + "/login.jsp");//在控制台上输出测试信息System.out.println("恭喜！注册成功，跳转到登录页面！");} else {// 设置session属性session.setAttribute("registerMsg", "遗憾，注册失败！");// 重定向到注册页面response.sendRedirect(request.getContextPath() + "/frontend/register.jsp");System.out.println("遗憾！注册失败！跳转到注册页面！");}}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

下面我们来进行测试
(1),启动服务器，访问

我们回到服务端控制台查看结果为：

此时我们去Navicat查看数据库是否添加了新的用户

(2)在次启动服务器，
在下面我们可以看到号码的长度为11，那当我们将号码输出不止11位时，是会注册失败的，那我们在注册栏里故意将号码输出12个进行注册,

在控制台查看结果：

SQL异常信息

在控制台除了出现“注册失败，跳转到注册页面”，还会出现一大串的SQL异常信息，这里看着就不是很舒服，我们可以修改一下:

再次运行查看：
再次在地址栏里故意输入12位号码，

再次回到服务台，查看结果：

4、显示类别处理类（ShowCategoryServlet）

package net.wlq.shop.servlet;/*** 功能：显示类别控制程序* 作者：wlq* 日期：2019年12月9日*/import java.io.IOException;
import java.util.List;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 net.wlq.shop.bean.Category;
import net.wlq.shop.service.CategoryService;@WebServlet("/showCategory")
public class ShowCategoryServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 创建类别服务对象CategoryService categoryService = new CategoryService();// 获取全部商品类别List<Category> categories = categoryService.findAllCategories();// 获取session对象HttpSession session = request.getSession();// 把商品类别列表以属性的方式保存到session里session.setAttribute("categories", categories);// 重定向到显示商品类别页面（showCategory.jsp）response.sendRedirect(request.getContextPath() + "/frontend/showCategory.jsp");}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

下面我们来进行测试。
重启服务器，访问http://localhost:8080/simonshop/showCategory：

5, 显示商品列表的控制程序 (ShowProductServlet)

package net.wlq.shop.servlet;/*** 功能：显示商品列表的控制程序*     通过业务层访问后台数据，*     然后将数据返回给前台页面* 作者：华卫* 日期：2012年12月9日*/import java.io.IOException;
import java.util.List;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 net.wlq.shop.bean.Product;
import net.wlq.shop.service.CategoryService;
import net.wlq.shop.service.ProductService;@WebServlet("/showProduct")
public class ShowProductServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 获取类别标识符int categoryId = Integer.parseInt(request.getParameter("categoryId"));// 创建商品类别服务对象CategoryService categoryService = new CategoryService();// 由类别标识符获取类别名String categoryName = categoryService.findCategoryById(categoryId).getName();// 创建商品服务对象ProductService productService = new ProductService();// 获取指定商品类别的商品列表List<Product> products = productService.findProductsByCategoryId(categoryId);// 获取session对象HttpSession session = request.getSession();// 把商品列表对象以属性的方式保存到session里session.setAttribute("products", products);// 重定向到显示商品信息页面response.sendRedirect(request.getContextPath() + "/frontend/showProduct.jsp?categoryName=" + categoryName);//在服务器端控制台输出测试信息for (int i = 0; i<products.size();i++){System.out.println(products.get(i));}}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

下面我们来进行测试
重启服务器，访问http://localhost:8080/simonshop/ShowProduct?categoryid=1

上面报500的错误，我们需要修改一下代码：ShowProductServlet类里面的

再次启动服务：

控制台信息：

6、显示购物车处理类（ShowCartServlet）

package net.wlq.shop.servlet;/*** 功能：显示购物车控制程序* 作者：wlq* 日期：2019年12月16日*/import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;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 net.wlq.shop.bean.Product;
import net.wlq.shop.service.ProductService;@WebServlet("/showCart")
public class ShowCartServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 获取商品类别标识符int categoryId = Integer.parseInt(request.getParameter("categoryId"));// 获取session对象HttpSession session = request.getSession();// 获取购物车LinkedHashMap<Integer, Integer> cart = (LinkedHashMap<Integer, Integer>) session.getAttribute("cart");// 判断购物车是否为空if (cart != null) {// 定义购物表List<HashMap<String, Object>> shoppingTable = new ArrayList<HashMap<String, Object>>();// 创建商品服务对象ProductService productService = new ProductService();// 购物总金额double totalPrice = 0.0;// 遍历购物车for (Integer id : cart.keySet()) {// 获取商品对象Product product = productService.findProductById(id);// 生成购物表记录HashMap<String, Object> shoppingItem = new HashMap<String, Object>();shoppingItem.put("id", product.getId());shoppingItem.put("name", product.getName());shoppingItem.put("price", product.getPrice());shoppingItem.put("amount", cart.get(id));shoppingItem.put("sum", product.getPrice() * cart.get(id));// 将购物表记录添加到购物表中shoppingTable.add(shoppingItem);// 累加购买总金额totalPrice = totalPrice + (Double) shoppingItem.get("sum");}// 将购物表和购买总金额保存到session里session.setAttribute("shoppingTable", shoppingTable);session.setAttribute("totalPrice", totalPrice);// 重定向到显示商品控制程序response.sendRedirect(request.getContextPath() + "/showProduct?categoryId=" + categoryId);} else {System.out.println("购物车里没有类别号为[" + categoryId + "]的商品！");}}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

重启服务器，访问：http://localhost:8080/simonshop/showCart?categoryId=1

之后我们到控制台查看结果：

7、操作购物车处理类（OperateCartServlet）

package net.hw.shop.servlet;
/*** 功能：操作购物车控制程序* 作者：华卫* 日期：2019年12月14日*/import java.io.IOException;
import java.util.LinkedHashMap;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 net.hw.shop.service.ProductService;@WebServlet("/operateCart")
public class OperateCartServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 获取商品标识符int id = Integer.parseInt(request.getParameter("id"));// 获取商品操作String operation = request.getParameter("operation");// 从session里获取购物车（键：商品标识符；值：购买数量）LinkedHashMap<Integer, Integer> cart = (LinkedHashMap<Integer, Integer>) request.getSession().getAttribute("cart");// 判断购物车是否为空if (cart == null) {// 创建购物车cart = new LinkedHashMap<Integer, Integer>();// 将购物车保存到session里，便于用户在不同页面访问购物车request.getSession().setAttribute("cart", cart);}if (operation.equals("add")) {// 将商品添加到购物车if (cart.containsKey(id)) { // 该商品已购买过// 购买数量增加1cart.put(id, cart.get(id) + 1);} else { // 该商品未曾购买// 购买数量设置为1cart.put(id, 1);}} else if (operation.equals("delete")){// 将商品从购物车删除if (cart.get(id) > 1) {// 购买数量减少1cart.put(id, cart.get(id) - 1);} else {// 从购物车里删除该商品cart.remove(id);}}// 创建商品服务对象ProductService productService = new ProductService();// 获取该商品类别标识符int categoryId = productService.findProductById(id).getCategoryId();// 重定向到显示购物车控制程序response.sendRedirect(request.getContextPath() + "/showCart?categoryId=" + categoryId);}
}

测试结果截图：

8、生成订单处理类（MakeOrderServlet）

package net.wlq.shop.servlet;/*** 功能：生成订单控制程序* 作者：wlq* 日期：2019年12月16日*/import java.io.IOException;
import java.sql.Timestamp;
import java.util.Date;
import java.util.List;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 net.wlq.shop.bean.Order;
import net.wlq.shop.bean.User;
import net.wlq.shop.service.OrderService;
import net.wlq.shop.service.UserService;
import net.wlq.shop.service.OrderService;
import net.wlq.shop.service.UserService;@WebServlet("/makeOrder")
public class MakeOrderServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 设置请求对象的字符编码request.setCharacterEncoding("utf-8");// 获取表单提交数据String username = request.getParameter("username");String telephone = request.getParameter("telephone");Double totalPrice = Double.parseDouble(request.getParameter("totalPrice"));String deliveryAddress = request.getParameter("deliveryAddress");// 创建订单对象Order order = new Order();// 设置订单属性order.setUsername(username);order.setTotalPrice(totalPrice);order.setTelephone(telephone);order.setDeliveryAddress(deliveryAddress);order.setOrderTime(new Date());// 创建订单服务OrderService orderService = new OrderService();// 添加订单orderService.addOrder(order);// 获取最后一个订单Order lastOrder = orderService.findLastOrder();// 保存到session里request.getSession().setAttribute("lastOrder", lastOrder);// 重定向到显示订单页面response.sendRedirect(request.getContextPath() + "/frontend/showOrder.jsp");}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

9、支付处理类（PayServlet）

package net.wlq.shop.servlet;/*** 功能：支付处理程序* 作者：wlq* 日期：2019年12月16日*/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 java.io.IOException;@WebServlet("/pay")
public class PayServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 设置请求对象的字符编码request.setCharacterEncoding("utf-8");///// 待做部分// 设置session失效request.getSession().invalidate();// 重定向到登录页面response.sendRedirect(request.getContextPath() + "/login.jsp");}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

10、显示用户处理类（ShowUserServlet）

package net.wlq.shop.servlet;/*** 功能：显示用户控制程序* 作者：wlq* 日期：2019年12月15日*/import java.io.IOException;
import java.util.List;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 net.wlq.shop.bean.User;
import net.wlq.shop.service.UserService;@WebServlet("/showUser")
public class ShowUserServlet extends HttpServlet {private static final long serialVersionUID = 1L;protected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {// 创建用户服务对象UserService userService = new UserService();// 获取全部用户List<User> users = userService.findAllUsers();// 获取session对象HttpSession session = request.getSession();// 把用户列表以属性的方式保存到session里session.setAttribute("users", users);// 重定向到显示用户页面（showUser.jsp）response.sendRedirect(request.getContextPath() + "/backend/showUser.jsp");// 在控制台输出所有用户信息for (User user: users) {System.out.println(user);}}protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}
}

测试结果截图：

重启服务器，访问：http://localhost:8080/simonshop/showUser

当我们查看控制台结果时：

我们需要修改一下代码，需要修改ConnectionManager里面的

这样我们就能明显的知道错误，而不是向上面那样就只是简单的说你报了一个指针异常，但是没有明确的错误，在下面的截图中我们可以知道错误的原因是因为数据库连接不成功的原因，这时我们需要去检查mysql服务是否启动，或者看看ConnectionManager代码里面是否有错。

这时我们再启动服务器查看：

再回到控制台会发现有新的信息：