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Java Web学习(33)： 阶段小项目使用MVC模型实现购物车效果（已上传至码云）

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  • Post category:java



重新编辑后源码压缩包上传至码云，地址：



https://gitee.com/lhw1320/codes/d4bkq1rp97uc2venfz3lw79

项目概述

前面的时候我写过一个商品浏记录的小例子，这一次我们使用实现购物车效果。前面的例子是：

http://blog.csdn.net/erlian1992/article/details/52047258。这一次在此基础上来采用的是MVC三层模型实现

(JSP+Servlet+dao)来实现这个小项目。

三层架构：

JSP视图层

Servlet控制层

dao模型层

DB数据库层

编码实现：

首先先来数据库脚本items.sql： 

/*
Navicat MySQL Data Transfer


Source Server         : MySQL50
Source Server Version : 50067
Source Host           : localhost:3306
Source Database       : shopping


Target Server Type    : MYSQL
Target Server Version : 50067
File Encoding         : 65001


Date: 2016-08-01 12:12:31
*/


SET FOREIGN_KEY_CHECKS=0;


-- ----------------------------
-- Table structure for items
-- ----------------------------
DROP TABLE IF EXISTS `items`;
CREATE TABLE `items` (
  `id` int(11) NOT NULL auto_increment,
  `name` varchar(50) default NULL,
  `city` varchar(50) default NULL,
  `price` int(11) default NULL,
  `number` int(11) default NULL,
  `picture` varchar(500) default NULL,
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;


-- ----------------------------
-- Records of items
-- ----------------------------
INSERT INTO `items` VALUES ('1', '沃特篮球鞋', '佛山', '180', '500', '001.jpg');
INSERT INTO `items` VALUES ('2', '安踏运动鞋', '福州', '120', '800', '002.jpg');
INSERT INTO `items` VALUES ('3', '耐克运动鞋', '广州', '500', '1000', '003.jpg');
INSERT INTO `items` VALUES ('4', '阿迪达斯T血衫', '上海', '388', '600', '004.jpg');
INSERT INTO `items` VALUES ('5', '李宁文化衫', '广州', '180', '900', '005.jpg');
INSERT INTO `items` VALUES ('6', '小米3', '北京', '1999', '3000', '006.jpg');
INSERT INTO `items` VALUES ('7', '小米2S', '北京', '1299', '1000', '007.jpg');
INSERT INTO `items` VALUES ('8', 'thinkpad笔记本', '北京', '6999', '500', '008.jpg');
INSERT INTO `items` VALUES ('9', 'dell笔记本', '北京', '3999', '500', '009.jpg');
INSERT INTO `items` VALUES ('10', 'ipad5', '北京', '5999', '500', '010.jpg');

我们再来连接MySQL数据库工具类DBHelper

：
 

package com.util;


import java.sql.Connection;
import java.sql.DriverManager;


/**
 * 连接MySQL数据库工具类
 * @author Administrator
 * @date 2016年08月01日
 */
public class DBHelper {
   
	//数据库驱动
	private static final String driver = "com.mysql.jdbc.Driver"; 
	//连接数据库的URL地址
	private static final String url="jdbc:mysql://localhost:3306/shopping?useUnicode=true&characterEncoding=UTF-8"; 
	//数据库的用户名
	private static final String username="root";
	//数据库的密码
	private static final String password="root";
    //Connection连接对象conn
	private static Connection conn=null;
	
	//静态代码块负责加载驱动
	static {
		try{
			Class.forName(driver);
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	
	//单例模式返回数据库连接对象
	public static Connection getConnection() throws Exception{
		if(conn==null){
			conn = DriverManager.getConnection(url, username, password);
			return conn;
		}else{
			return conn;
		}
	}
	
	public static void main(String[] args) {
		//测试数据库是否连接正常
		try{
		   Connection conn = DBHelper.getConnection();
		   if(conn!=null){
			   System.out.println("数据库连接正常！");
		   }else{
			   System.out.println("数据库连接异常！");
		   }
		}catch(Exception e){
			e.printStackTrace();
		}


	}
}											



	//数据库驱动
	private static final String driver = "com.mysql.jdbc.Driver"; 
	//连接数据库的URL地址
	private static final String url="jdbc:mysql://localhost:3306/shopping?useUnicode=true&characterEncoding=UTF-8"; 
	//数据库的用户名
	private static final String username="root";
	//数据库的密码
	private static final String password="root";
    //Connection连接对象conn
	private static Connection conn=null;
	
	//静态代码块负责加载驱动
	static {
		try{
			Class.forName(driver);
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	
	//单例模式返回数据库连接对象
	public static Connection getConnection() throws Exception{
		if(conn==null){
			conn = DriverManager.getConnection(url, username, password);
			return conn;
		}else{
			return conn;
		}
	}
	
	public static void main(String[] args) {
		//测试数据库是否连接正常
		try{
		   Connection conn = DBHelper.getConnection();
		   if(conn!=null){
			   System.out.println("数据库连接正常！");
		   }else{
			   System.out.println("数据库连接异常！");
		   }
		}catch(Exception e){
			e.printStackTrace();
		}


	}
}

再来创建两个实体类，一个是对应items数据表的Items.java 

package com.entity;


/**
 * 商品实体类
 * @author Administrator
 * @date 2016年08月01日
 */
public class Items {


	private int id; // 商品编号
	private String name; // 商品名称
	private String city; // 产地
	private int price; // 价格
	private int number; // 库存
	private String picture; // 商品图片


	//保留此不带参数的构造方法
	public Items(){
		
	}
		
	//不带参数的构造方法
	public Items(int id,String name,String city,int price,int number,String picture){
		this.id = id;
		this.name = name;
		this.city = city;
		this.picture = picture;
		this.price = price;
		this.number = number;	
	}
	
	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 String getCity() {
		return city;
	}


	public void setCity(String city) {
		this.city = city;
	}


	public int getPrice() {
		return price;
	}


	public void setPrice(int price) {
		this.price = price;
	}


	public int getNumber() {
		return number;
	}


	public void setNumber(int number) {
		this.number = number;
	}


	public String getPicture() {
		return picture;
	}


	public void setPicture(String picture) {
		this.picture = picture;
	}
	
	@Override
	public int hashCode() {
		return this.getId()+this.getName().hashCode();
	}


	@Override
	public boolean equals(Object obj) {
		if(this==obj){
			return true;
		}
		
		if(obj instanceof Items){
			Items i = (Items)obj;
			if(this.getId()==i.getId()&&this.getName().equals(i.getName())){
				return true;
			}else{
				return false;
			}
		}else{
			return false;
		}
		
	}


	@Override
	public String toString(){
		return "商品编号："+this.getId()+"，商品名称："+this.getName();
	}


}	private int id; // 商品编号
	private String name; // 商品名称
	private String city; // 产地
	private int price; // 价格
	private int number; // 库存
	private String picture; // 商品图片


	//保留此不带参数的构造方法
	public Items(){
		
	}
		
	//不带参数的构造方法
	public Items(int id,String name,String city,int price,int number,String picture){
		this.id = id;
		this.name = name;
		this.city = city;
		this.picture = picture;
		this.price = price;
		this.number = number;	
	}
	
	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 String getCity() {
		return city;
	}


	public void setCity(String city) {
		this.city = city;
	}


	public int getPrice() {
		return price;
	}


	public void setPrice(int price) {
		this.price = price;
	}


	public int getNumber() {
		return number;
	}


	public void setNumber(int number) {
		this.number = number;
	}


	public String getPicture() {
		return picture;
	}


	public void setPicture(String picture) {
		this.picture = picture;
	}
	
	@Override
	public int hashCode() {
		return this.getId()+this.getName().hashCode();
	}


	@Override
	public boolean equals(Object obj) {
		if(this==obj){
			return true;
		}
		
		if(obj instanceof Items){
			Items i = (Items)obj;
			if(this.getId()==i.getId()&&this.getName().equals(i.getName())){
				return true;
			}else{
				return false;
			}
		}else{
			return false;
		}
		
	}


	@Override
	public String toString(){
		return "商品编号："+this.getId()+"，商品名称："+this.getName();
	}


}

一个是Cart.java 

package com.entity;


import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;


/**
 * 购物车实体类(添加、删除和计算价格)
 * @author Administrator
 * @date 2016年08月01日
 */
public class Cart {
	
	    //购买商品的集合
		private HashMap<Items,Integer> goods;
		
		//购物车的总金额
		private double totalPrice;


		//构造方法
		public Cart(){
			goods = new HashMap<Items,Integer>();
			totalPrice = 0.0;
		}
		
		
		public HashMap<Items, Integer> getGoods() {
			return goods;
		}


		public void setGoods(HashMap<Items, Integer> goods) {
			this.goods = goods;
		}


		public double getTotalPrice() {
			return totalPrice;
		}


		public void setTotalPrice(double totalPrice) {
			this.totalPrice = totalPrice;
		}
		
		//添加商品进购物车的方法
		public boolean addGoodsInCart(Items item ,int number){
			if(goods.containsKey(item)){
				goods.put(item, goods.get(item)+number);
			}else{
				goods.put(item, number);	
			}
			calTotalPrice(); //重新计算购物车的总金额
			return true;
		}
		
		//删除商品的方法
		public boolean removeGoodsFromCart(Items item){
			goods.remove(item);
			calTotalPrice(); //重新计算购物车的总金额
			return true;
		}
		
		//统计购物车的总金额
		public double calTotalPrice(){
			double sum = 0.0;
			Set<Items> keys = goods.keySet(); //获得键的集合
			Iterator<Items> it = keys.iterator(); //获得迭代器对象
		    while(it.hasNext()){
		    	Items i = it.next();
		    	sum += i.getPrice()* goods.get(i);
		    }
		    this.setTotalPrice(sum); //设置购物车的总金额
		    return this.getTotalPrice();
		}
		
		public static void main(String[] args) {
			
			//先创建两个商品对象
			Items i1 = new Items(1,"沃特篮球鞋","温州",200,500,"001.jpg");
			Items i2 = new Items(2,"李宁运动鞋","广州",300,500,"002.jpg");
			Items i3 = new Items(1,"沃特篮球鞋","温州",200,500,"001.jpg");
			
			Cart cart = new Cart();
			cart.addGoodsInCart(i1, 1);
			cart.addGoodsInCart(i2, 2);
			//再次购买沃特篮球鞋，购买3双
			cart.addGoodsInCart(i3, 3);
			
			
			//遍历购物车商品的集合
			Set<Map.Entry<Items, Integer>> items= cart.getGoods().entrySet();
			for(Map.Entry<Items, Integer> obj:items){
				System.out.println(obj);
			}	
			
			System.out.println("购物车的总金额："+cart.getTotalPrice());
		}


}	
	    //购买商品的集合
		private HashMap<Items,Integer> goods;
		
		//购物车的总金额
		private double totalPrice;


		//构造方法
		public Cart(){
			goods = new HashMap<Items,Integer>();
			totalPrice = 0.0;
		}
		
		
		public HashMap<Items, Integer> getGoods() {
			return goods;
		}


		public void setGoods(HashMap<Items, Integer> goods) {
			this.goods = goods;
		}


		public double getTotalPrice() {
			return totalPrice;
		}


		public void setTotalPrice(double totalPrice) {
			this.totalPrice = totalPrice;
		}
		
		//添加商品进购物车的方法
		public boolean addGoodsInCart(Items item ,int number){
			if(goods.containsKey(item)){
				goods.put(item, goods.get(item)+number);
			}else{
				goods.put(item, number);	
			}
			calTotalPrice(); //重新计算购物车的总金额
			return true;
		}
		
		//删除商品的方法
		public boolean removeGoodsFromCart(Items item){
			goods.remove(item);
			calTotalPrice(); //重新计算购物车的总金额
			return true;
		}
		
		//统计购物车的总金额
		public double calTotalPrice(){
			double sum = 0.0;
			Set<Items> keys = goods.keySet(); //获得键的集合
			Iterator<Items> it = keys.iterator(); //获得迭代器对象
		    while(it.hasNext()){
		    	Items i = it.next();
		    	sum += i.getPrice()* goods.get(i);
		    }
		    this.setTotalPrice(sum); //设置购物车的总金额
		    return this.getTotalPrice();
		}
		
		public static void main(String[] args) {
			
			//先创建两个商品对象
			Items i1 = new Items(1,"沃特篮球鞋","温州",200,500,"001.jpg");
			Items i2 = new Items(2,"李宁运动鞋","广州",300,500,"002.jpg");
			Items i3 = new Items(1,"沃特篮球鞋","温州",200,500,"001.jpg");
			
			Cart cart = new Cart();
			cart.addGoodsInCart(i1, 1);
			cart.addGoodsInCart(i2, 2);
			//再次购买沃特篮球鞋，购买3双
			cart.addGoodsInCart(i3, 3);
			
			
			//遍历购物车商品的集合
			Set<Map.Entry<Items, Integer>> items= cart.getGoods().entrySet();
			for(Map.Entry<Items, Integer> obj:items){
				System.out.println(obj);
			}	
			
			System.out.println("购物车的总金额："+cart.getTotalPrice());
		}


}

接下来是dao层ItemsDAO.java 

package com.dao;


import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;


import com.util.DBHelper;
import com.entity.Items;


/**
 * 商品的业务逻辑类
 * @author Administrator
 * @date 2016年08月01日
 */
public class ItemsDAO {


	// 获得所有的商品信息
	public ArrayList<Items> getAllItems() {
		Connection conn = null;//数据库连接对象
		PreparedStatement stmt = null;//SQL语句对象
		ResultSet rs = null;//数据集对象
		
		ArrayList<Items> list = new ArrayList<Items>(); // 商品集合
		
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from items;"; // 查询SQL语句
			stmt = conn.prepareStatement(sql);
			rs = stmt.executeQuery();//获取数据集
			
			while (rs.next()) {
				Items item = new Items();
				item.setId(rs.getInt("id"));
				item.setName(rs.getString("name"));
				item.setCity(rs.getString("city"));
				item.setNumber(rs.getInt("number"));
				item.setPrice(rs.getInt("price"));
				item.setPicture(rs.getString("picture"));
				list.add(item);// 把一个商品加入集合
			}
			return list; // 返回集合。
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			// 释放数据集对象
			if (rs != null) {
				try {
					rs.close();
					rs = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
			// 释放SQL语句对象
			if (stmt != null) {
				try {
					stmt.close();
					stmt = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}


	}


	// 根据商品编号ID获得商品详细资料
	public Items getItemsById(int id) {
		Connection conn = null;
		PreparedStatement stmt = null;
		ResultSet rs = null;
		
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from items where id=?;"; // SQL查询语句
			stmt = conn.prepareStatement(sql);
			//把id的值赋给SQL查询语句中第一个问号
			stmt.setInt(1, id);
			rs = stmt.executeQuery();
			
			if (rs.next()) {
				Items item = new Items();
				item.setId(rs.getInt("id"));
				item.setName(rs.getString("name"));
				item.setCity(rs.getString("city"));
				item.setNumber(rs.getInt("number"));
				item.setPrice(rs.getInt("price"));
				item.setPicture(rs.getString("picture"));
				return item;
			} else {
				return null;
			}


		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			// 释放数据集对象
			if (rs != null) {
				try {
					rs.close();
					rs = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
			// 释放语句对象
			if (stmt != null) {
				try {
					stmt.close();
					stmt = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}


		}
	}
	
	
	//获取最近浏览的前五条商品信息
	public ArrayList<Items> getViewList(String list){
		System.out.println("list:"+list);
		ArrayList<Items> itemlist = new ArrayList<Items>();
		int iCount=5; //每次返回前五条记录
		if(list!=null&&list.length()>0){
		    String[] arr = list.split(",");
		    System.out.println("arr.length="+arr.length);
		    //如果商品记录大于等于5条
		    if(arr.length>=5){
		       for(int i=arr.length-1;i>=arr.length-iCount;i--){
		    	  itemlist.add(getItemsById(Integer.parseInt(arr[i])));  
		       }
		    }else{
		    	for(int i=arr.length-1;i>=0;i--){
		    		itemlist.add(getItemsById(Integer.parseInt(arr[i])));
		    	}
		    }
		    return itemlist;
		}else{
			return null;
		}
	}


}	// 获得所有的商品信息
	public ArrayList<Items> getAllItems() {
		Connection conn = null;//数据库连接对象
		PreparedStatement stmt = null;//SQL语句对象
		ResultSet rs = null;//数据集对象
		
		ArrayList<Items> list = new ArrayList<Items>(); // 商品集合
		
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from items;"; // 查询SQL语句
			stmt = conn.prepareStatement(sql);
			rs = stmt.executeQuery();//获取数据集
			
			while (rs.next()) {
				Items item = new Items();
				item.setId(rs.getInt("id"));
				item.setName(rs.getString("name"));
				item.setCity(rs.getString("city"));
				item.setNumber(rs.getInt("number"));
				item.setPrice(rs.getInt("price"));
				item.setPicture(rs.getString("picture"));
				list.add(item);// 把一个商品加入集合
			}
			return list; // 返回集合。
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			// 释放数据集对象
			if (rs != null) {
				try {
					rs.close();
					rs = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
			// 释放SQL语句对象
			if (stmt != null) {
				try {
					stmt.close();
					stmt = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}


	}


	// 根据商品编号ID获得商品详细资料
	public Items getItemsById(int id) {
		Connection conn = null;
		PreparedStatement stmt = null;
		ResultSet rs = null;
		
		try {
			conn = DBHelper.getConnection();
			String sql = "select * from items where id=?;"; // SQL查询语句
			stmt = conn.prepareStatement(sql);
			//把id的值赋给SQL查询语句中第一个问号
			stmt.setInt(1, id);
			rs = stmt.executeQuery();
			
			if (rs.next()) {
				Items item = new Items();
				item.setId(rs.getInt("id"));
				item.setName(rs.getString("name"));
				item.setCity(rs.getString("city"));
				item.setNumber(rs.getInt("number"));
				item.setPrice(rs.getInt("price"));
				item.setPicture(rs.getString("picture"));
				return item;
			} else {
				return null;
			}


		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			// 释放数据集对象
			if (rs != null) {
				try {
					rs.close();
					rs = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
			// 释放语句对象
			if (stmt != null) {
				try {
					stmt.close();
					stmt = null;
				} catch (Exception e) {
					e.printStackTrace();
				}
			}


		}
	}
	
	
	//获取最近浏览的前五条商品信息
	public ArrayList<Items> getViewList(String list){
		System.out.println("list:"+list);
		ArrayList<Items> itemlist = new ArrayList<Items>();
		int iCount=5; //每次返回前五条记录
		if(list!=null&&list.length()>0){
		    String[] arr = list.split(",");
		    System.out.println("arr.length="+arr.length);
		    //如果商品记录大于等于5条
		    if(arr.length>=5){
		       for(int i=arr.length-1;i>=arr.length-iCount;i--){
		    	  itemlist.add(getItemsById(Integer.parseInt(arr[i])));  
		       }
		    }else{
		    	for(int i=arr.length-1;i>=0;i--){
		    		itemlist.add(getItemsById(Integer.parseInt(arr[i])));
		    	}
		    }
		    return itemlist;
		}else{
			return null;
		}
	}


}

最后是Servlet控制层中的CartServlet： 

package com.servlet;


import java.io.IOException;


import javax.servlet.ServletConfig;
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 com.dao.ItemsDAO;
import com.entity.Cart;
import com.entity.Items;


/**
 * Servlet implementation class CarServlet
 */
@WebServlet(name="CartServlet" ,urlPatterns={"/CartServlet"})
public class CartServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
    
	private String action;//表示购物车动作：add,show,delete
	private ItemsDAO idao = new ItemsDAO();//商品业务逻辑类对象
	
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CartServlet() {
        super();
        // TODO Auto-generated constructor stub
    }


	/**
	 * @see Servlet#init(ServletConfig)
	 */
	public void init(ServletConfig config) throws ServletException {
		// TODO Auto-generated method stub
	}


	/**
	 * @see Servlet#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}


	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request, response);
	}


	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("text/html;charset=UTF-8");
		
		//PrintWriter out = response.getWriter();
		if(request.getParameter("action")!=null){
			this.action = request.getParameter("action");
			
			//添加商品进购物车
			if(action.equals("add")) {
				if(addToCart(request,response)){
					request.getRequestDispatcher("/success.jsp").forward(request, response);
				}else{
					request.getRequestDispatcher("/failure.jsp").forward(request, response);
				}
			}
			
			//显示购物车
			if(action.equals("show")){
				request.getRequestDispatcher("/cart.jsp").forward(request, response);
			}
			
			//如果是执行删除购物车中的商品
			if(action.equals("delete")) {
				if(deleteFromCart(request,response)){
					request.getRequestDispatcher("/cart.jsp").forward(request, response);
				}else{
					request.getRequestDispatcher("/cart.jsp").forward(request, response);
				}
			}
		}
		
	}


	//添加商品进购物车的方法
	private boolean addToCart(HttpServletRequest request, HttpServletResponse response){
		String id = request.getParameter("id");
		String number = request.getParameter("num");
		Items item = idao.getItemsById(Integer.parseInt(id));
		
		//是否是第一次给购物车添加商品，需要给session中创建一个新的购物车对象
		if(request.getSession().getAttribute("cart") == null){
			Cart cart = new Cart();
			request.getSession().setAttribute("cart",cart);
		}
		
		//不是第一次添加进购物车
		Cart cart = (Cart)request.getSession().getAttribute("cart");
		
		if(cart.addGoodsInCart(item, Integer.parseInt(number))){
			return true;
		}else{
			return false;
		}
		
	}
	
	//从购物车中删除商品
	private boolean deleteFromCart(HttpServletRequest request, HttpServletResponse response){
		String id = request.getParameter("id");
		Cart cart = (Cart)request.getSession().getAttribute("cart");
	    Items item = idao.getItemsById(Integer.parseInt(id));
	    
	    if(cart.removeGoodsFromCart(item)){
	    	return true;
	    }else{
	    	return false;
	    }
	}


}	private static final long serialVersionUID = 1L;
    
	private String action;//表示购物车动作：add,show,delete
	private ItemsDAO idao = new ItemsDAO();//商品业务逻辑类对象
	
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CartServlet() {
        super();
        // TODO Auto-generated constructor stub
    }


	/**
	 * @see Servlet#init(ServletConfig)
	 */
	public void init(ServletConfig config) throws ServletException {
		// TODO Auto-generated method stub
	}


	/**
	 * @see Servlet#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}


	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request, response);
	}


	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("text/html;charset=UTF-8");
		
		//PrintWriter out = response.getWriter();
		if(request.getParameter("action")!=null){
			this.action = request.getParameter("action");
			
			//添加商品进购物车
			if(action.equals("add")) {
				if(addToCart(request,response)){
					request.getRequestDispatcher("/success.jsp").forward(request, response);
				}else{
					request.getRequestDispatcher("/failure.jsp").forward(request, response);
				}
			}
			
			//显示购物车
			if(action.equals("show")){
				request.getRequestDispatcher("/cart.jsp").forward(request, response);
			}
			
			//如果是执行删除购物车中的商品
			if(action.equals("delete")) {
				if(deleteFromCart(request,response)){
					request.getRequestDispatcher("/cart.jsp").forward(request, response);
				}else{
					request.getRequestDispatcher("/cart.jsp").forward(request, response);
				}
			}
		}
		
	}


	//添加商品进购物车的方法
	private boolean addToCart(HttpServletRequest request, HttpServletResponse response){
		String id = request.getParameter("id");
		String number = request.getParameter("num");
		Items item = idao.getItemsById(Integer.parseInt(id));
		
		//是否是第一次给购物车添加商品，需要给session中创建一个新的购物车对象
		if(request.getSession().getAttribute("cart") == null){
			Cart cart = new Cart();
			request.getSession().setAttribute("cart",cart);
		}
		
		//不是第一次添加进购物车
		Cart cart = (Cart)request.getSession().getAttribute("cart");
		
		if(cart.addGoodsInCart(item, Integer.parseInt(number))){
			return true;
		}else{
			return false;
		}
		
	}
	
	//从购物车中删除商品
	private boolean deleteFromCart(HttpServletRequest request, HttpServletResponse response){
		String id = request.getParameter("id");
		Cart cart = (Cart)request.getSession().getAttribute("cart");
	    Items item = idao.getItemsById(Integer.parseInt(id));
	    
	    if(cart.removeGoodsFromCart(item)){
	    	return true;
	    }else{
	    	return false;
	    }
	}


}

再来视图层：

商品列表页面index.jsp 

<%@page import="com.entity.Items"%>
<%@page import="com.dao.ItemsDAO"%>
<%@page import="java.util.ArrayList"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>商品列表页面</title>
<style type="text/css">
hr{
   border-color:FF7F00; 
}


div{
   float:left;
   margin: 10px;
}


div dd{
   margin:0px;
   font-size:10pt;
}


div dd.dd_name{
   color:blue;
}


div dd.dd_city{
   color:#000;
}
</style>
</head>
<body>
    <h1>商品展示</h1>
    <hr>
    <center>
    <table width="750" height="60" cellpadding="0" cellspacing="0" border="0">
      <tr>
        <td>
           <!-- 商品循环开始 -->
           
           <% 
               //防止中文乱码
               request.setCharacterEncoding("UTF-8");
            
               ItemsDAO itemsDao = new ItemsDAO(); 
               ArrayList<Items> list = itemsDao.getAllItems();
               if(list!=null&&list.size()>0){
	               for(int i=0;i<list.size();i++){
	                  Items item = list.get(i);
           %>   
          <div>
             <dl>
               <dt>
                 <a href="details.jsp?id=<%=item.getId()%>">
                      <img src="images/<%=item.getPicture()%>" width="120" height="90" border="1"/>
                 </a>
               </dt>
                  <dd class="dd_name"><%=item.getName() %></dd> 
                  <dd class="dd_city">产地:<%=item.getCity() %>&nbsp;&nbsp;价格:￥ <%=item.getPrice() %></dd> 
             </dl>
          </div>
          <!-- 商品循环结束 -->
        
          <%
                   }
              } 
          %>
        </td>
      </tr>
    </table>
    </center>
</body>
</html>	               for(int i=0;i<list.size();i++){
	                  Items item = list.get(i);
           %>   
          <div>
             <dl>
               <dt>
                 <a href="details.jsp?id=<%=item.getId()%>">
                      <img src="images/<%=item.getPicture()%>" width="120" height="90" border="1"/>
                 </a>
               </dt>
                  <dd class="dd_name"><%=item.getName() %></dd> 
                  <dd class="dd_city">产地:<%=item.getCity() %>&nbsp;&nbsp;价格:￥ <%=item.getPrice() %></dd> 
             </dl>
          </div>
          <!-- 商品循环结束 -->
        
          <%
                   }
              } 
          %>
        </td>
      </tr>
    </table>
    </center>
</body>
</html>

商品详情页面details.jsp 

<%@page import="java.util.ArrayList"%>
<%@ page import="com.entity.Items"%>
<%@ page import="com.dao.ItemsDAO"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%
      String path = request.getContextPath();
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>商品详情页面</title>
<link href="css/main.css" rel="stylesheet" type="text/css" />
<script type="text/javascript" src="js/lhgcore.js"></script>
<script type="text/javascript" src="js/lhgdialog.js"></script>
<script type="text/javascript">    
    function selflog_show(id){ 
       var num =  document.getElementById("number").value; 
       J.dialog.get({id: 'haoyue_creat',title: '购物成功',width: 600,height:400, link: '<%=path%>/CartServlet?id='+id+'&num='+num+'&action=add', cover:true});
    }
     
    //商品数量增加
	function add() {
		var num = parseInt(document.getElementById("number").value);
		if (num < 100) {
			document.getElementById("number").value = ++num;
		}
	}
	
    //商品数量减少
	function sub() {
		var num = parseInt(document.getElementById("number").value);
		if (num > 1) {
			document.getElementById("number").value = --num;
		}
    }
</script>
<style type="text/css">
hr {
	border-color: FF7F00;
}


div {
	float: left;
	margin-left: 30px;
	margin-right: 30px;
	margin-top: 5px;
	margin-bottom: 5px;
}


div dd {
	margin: 0px;
	font-size: 10pt;
}


div dd.dd_name {
	color: blue;
}


div dd.dd_city {
	color: #000;
}


div #cart {
	margin: 0px auto;
	text-align: right;
}


span {
	padding: 0 2px;
	border: 1px #c0c0c0 solid;
	cursor: pointer;
}


a {
	text-decoration: none;
}
</style>
</head>
<body>
    <h1>商品详情</h1>
    <a href="index.jsp">首页</a> >> <a href="index.jsp">商品列表</a>
    <hr>
    <center>
      <table width="750" height="60" cellpadding="0" cellspacing="0" border="0">
        <tr>
          <!-- 商品详情 -->
          
          <% 
                 ItemsDAO itemDao = new ItemsDAO();
                 Items item = itemDao.getItemsById(Integer.parseInt(request.getParameter("id")));
                 if(item != null){
          %>
          
          <td width="70%" valign="top">
             <table>
               <tr>
                 <td rowspan="4"><img src="images/<%=item.getPicture()%>" width="200" height="160"/></td>
               </tr>
               <tr>
                 <td><B><%=item.getName() %></B></td> 
               </tr>
               <tr>
                 <td>产地：<%=item.getCity()%></td>
               </tr>
               <tr>
                 <td>价格：<%=item.getPrice() %>￥</td>
               </tr> 
               <tr>
                 <td>购买数量：
                       <span id="sub" onclick="sub();">-</span><input type="text" id="number" name="number" value="1" size="2" /><span id="add" onclick="add();">+</span>
                 </td>
               </tr> 
             </table>
             <div id="cart">
               <img src="images/buy_now.png" />
               <a href="javascript:selflog_show(<%=item.getId()%>)"><img src="images/in_cart.png" /></a>
               <a href="CartServlet?action=show"><img src="images/view_cart.jpg" /></a>
             </div>
          </td>
          
          <% 
                  }
          %>
          
          <% 
	               String list ="";
	               //从客户端获得Cookies集合
	               Cookie[] cookies = request.getCookies();
	               //遍历这个Cookies集合
	               if(cookies != null&&cookies.length > 0){
		               for(Cookie c:cookies){
		                   if(c.getName().equals("ListViewCookie")){
		                      list = c.getValue();
		                   }
		               }
		          }
              
	              //追加商品编号
	              list += request.getParameter("id")+",";
	              //如果浏览记录超过1000条，清零.
	              String[] arr = list.split(",");
	              if(arr != null&&arr.length > 0){
	                  if(arr.length>=1000){
	                      list = "";
	                  }
	              }
	              Cookie cookie = new Cookie("ListViewCookie",list);
	              response.addCookie(cookie);
          %>
          
          <!-- 浏览过的商品 -->
          <td width="30%" bgcolor="#EEE" align="center">
             <br>
             <b>您浏览过的商品</b><br>
             <!-- 循环开始 -->
             <% 
	                ArrayList<Items> itemlist = itemDao.getViewList(list);
	                if(itemlist!=null&&itemlist.size()>0 ){
	                    System.out.println("itemlist.size="+itemlist.size());
	                    for(Items i:itemlist){
                         
             %>
             <div>
             <dl>
               <dt>
                 <a href="details.jsp?id=<%=i.getId()%>"><img src="images/<%=i.getPicture() %>" width="120" height="90" border="1"/></a>
               </dt>
               <dd class="dd_name"><%=i.getName() %></dd> 
               <dd class="dd_city">产地:<%=i.getCity() %>&nbsp;&nbsp;价格:<%=i.getPrice() %> ￥ </dd> 
             </dl>
             </div>
             <% 
                        }
                   }
             %>
             <!-- 循环结束 -->
          </td>
        </tr>
      </table>
    </center>
</body>
</html>	function add() {
		var num = parseInt(document.getElementById("number").value);
		if (num < 100) {
			document.getElementById("number").value = ++num;
		}
	}
	
    //商品数量减少
	function sub() {
		var num = parseInt(document.getElementById("number").value);
		if (num > 1) {
			document.getElementById("number").value = --num;
		}
    }
</script>
<style type="text/css">
hr {
	border-color: FF7F00;
}


div {
	float: left;
	margin-left: 30px;
	margin-right: 30px;
	margin-top: 5px;
	margin-bottom: 5px;
}


div dd {
	margin: 0px;
	font-size: 10pt;
}


div dd.dd_name {
	color: blue;
}


div dd.dd_city {
	color: #000;
}


div #cart {
	margin: 0px auto;
	text-align: right;
}


span {
	padding: 0 2px;
	border: 1px #c0c0c0 solid;
	cursor: pointer;
}


a {
	text-decoration: none;
}
</style>
</head>
<body>
    <h1>商品详情</h1>
    <a href="index.jsp">首页</a> >> <a href="index.jsp">商品列表</a>
    <hr>
    <center>
      <table width="750" height="60" cellpadding="0" cellspacing="0" border="0">
        <tr>
          <!-- 商品详情 -->
          
          <% 
                 ItemsDAO itemDao = new ItemsDAO();
                 Items item = itemDao.getItemsById(Integer.parseInt(request.getParameter("id")));
                 if(item != null){
          %>
          
          <td width="70%" valign="top">
             <table>
               <tr>
                 <td rowspan="4"><img src="images/<%=item.getPicture()%>" width="200" height="160"/></td>
               </tr>
               <tr>
                 <td><B><%=item.getName() %></B></td> 
               </tr>
               <tr>
                 <td>产地：<%=item.getCity()%></td>
               </tr>
               <tr>
                 <td>价格：<%=item.getPrice() %>￥</td>
               </tr> 
               <tr>
                 <td>购买数量：
                       <span id="sub" οnclick="sub();">-</span><input type="text" id="number" name="number" value="1" size="2" /><span id="add" οnclick="add();">+</span>
                 </td>
               </tr> 
             </table>
             <div id="cart">
               <img src="images/buy_now.png" />
               <a href="javascript:selflog_show(<%=item.getId()%>)"><img src="images/in_cart.png" /></a>
               <a href="CartServlet?action=show"><img src="images/view_cart.jpg" /></a>
             </div>
          </td>
          
          <% 
                  }
          %>
          
          <% 
	               String list ="";
	               //从客户端获得Cookies集合
	               Cookie[] cookies = request.getCookies();
	               //遍历这个Cookies集合
	               if(cookies != null&&cookies.length > 0){
		               for(Cookie c:cookies){
		                   if(c.getName().equals("ListViewCookie")){
		                      list = c.getValue();
		                   }
		               }
		          }
              
	              //追加商品编号
	              list += request.getParameter("id")+",";
	              //如果浏览记录超过1000条，清零.
	              String[] arr = list.split(",");
	              if(arr != null&&arr.length > 0){
	                  if(arr.length>=1000){
	                      list = "";
	                  }
	              }
	              Cookie cookie = new Cookie("ListViewCookie",list);
	              response.addCookie(cookie);
          %>
          
          <!-- 浏览过的商品 -->
          <td width="30%" bgcolor="#EEE" align="center">
             <br>
             <b>您浏览过的商品</b><br>
             <!-- 循环开始 -->
             <% 
	                ArrayList<Items> itemlist = itemDao.getViewList(list);
	                if(itemlist!=null&&itemlist.size()>0 ){
	                    System.out.println("itemlist.size="+itemlist.size());
	                    for(Items i:itemlist){
                         
             %>
             <div>
             <dl>
               <dt>
                 <a href="details.jsp?id=<%=i.getId()%>"><img src="images/<%=i.getPicture() %>" width="120" height="90" border="1"/></a>
               </dt>
               <dd class="dd_name"><%=i.getName() %></dd> 
               <dd class="dd_city">产地:<%=i.getCity() %>&nbsp;&nbsp;价格:<%=i.getPrice() %> ￥ </dd> 
             </dl>
             </div>
             <% 
                        }
                   }
             %>
             <!-- 循环结束 -->
          </td>
        </tr>
      </table>
    </center>
</body>
</html>

购买成功页面success.jsp 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>购买成功页面</title>
</head>
<body>
     <center>
      <img src="images/add_cart_success.jpg"/>
      <hr>
      <% 
            String id = request.getParameter("id");
            String num = request.getParameter("num");
      %>
      您成功购买了<%=num %>件商品编号为<%=id %>的商品&nbsp;&nbsp;&nbsp;&nbsp;
      <br>
      <br>
      <br>
      
    </center>
</body>
</html>

购买失败页面failure.jsp 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>购买失败页面</title>
</head>
<body>
    <center>
      <img src="images/add_cart_failure.jpg"/>
      <hr>
      
      <br>
      <br>
      <br>
      
    </center>
</body>
</html>

购物车页面cart.jsp 

<%@page import="java.util.Iterator"%>
<%@page import="java.util.Set"%>
<%@page import="com.entity.Items"%>
<%@page import="java.util.HashMap"%>
<%@page import="com.entity.Cart"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>购物车页面</title>
<link type="text/css" rel="stylesheet" href="css/style1.css" />
<script type="text/javascript">
	function delcfm() {
		if (!confirm("确认要删除？")) {
			window.event.returnValue = false;
		}
	}
</script>
</head>


<body>
	<h1>我的购物车</h1>
	<a href="index.jsp">首页</a> >>
	<a href="index.jsp">商品列表</a>
	<hr>
	<div id="shopping">
		<form action="#" method="post">
			<table>
				<tr>
					<th>商品名称</th>
					<th>商品单价</th>
					<th>商品价格</th>
					<th>购买数量</th>
					<th>操作</th>
				</tr>
				<% 
				      //首先判断session中是否有购物车对象
				      if(request.getSession().getAttribute("cart")!=null){
				%>
				<!-- 循环的开始 -->
				<% 
				         Cart cart = (Cart)request.getSession().getAttribute("cart");
				         HashMap<Items,Integer> goods = cart.getGoods();
				         Set<Items> items = goods.keySet();
				         Iterator<Items> it = items.iterator();
				         
				         while(it.hasNext()){
				            Items i = it.next();
				%>
				<tr name="products" id="product_id_1">
					<td class="thumb">
					     <img src="images/<%=i.getPicture()%>" />
					     <a href=""><%=i.getName()%></a>
					</td>
					<td class="number"><%=i.getPrice() %></td>
					<td class="price" id="price_id_1">
					    <span><%=i.getPrice()*goods.get(i) %></span>
						<input type="hidden" value="" />
				    </td>
					<td class="number"><%=goods.get(i)%></td>
					<td class="delete"><a href="CartServlet?action=delete&id=<%=i.getId()%>" onclick="delcfm();">删除</a></td>
				</tr>
				<% 
				         }
				%>
				<!--循环的结束-->


			</table>
			<div class="total">
				<span id="total">总计：<%=cart.getTotalPrice() %>￥</span>
			</div>
			<% 
			    }
			 %>
			<div class="button">
				<input type="submit" value="" />
			</div>
		</form>
	</div>
</body>
</html>	function delcfm() {
		if (!confirm("确认要删除？")) {
			window.event.returnValue = false;
		}
	}
</script>
</head>


<body>
	<h1>我的购物车</h1>
	<a href="index.jsp">首页</a> >>
	<a href="index.jsp">商品列表</a>
	<hr>
	<div id="shopping">
		<form action="#" method="post">
			<table>
				<tr>
					<th>商品名称</th>
					<th>商品单价</th>
					<th>商品价格</th>
					<th>购买数量</th>
					<th>操作</th>
				</tr>
				<% 
				      //首先判断session中是否有购物车对象
				      if(request.getSession().getAttribute("cart")!=null){
				%>
				<!-- 循环的开始 -->
				<% 
				         Cart cart = (Cart)request.getSession().getAttribute("cart");
				         HashMap<Items,Integer> goods = cart.getGoods();
				         Set<Items> items = goods.keySet();
				         Iterator<Items> it = items.iterator();
				         
				         while(it.hasNext()){
				            Items i = it.next();
				%>
				<tr name="products" id="product_id_1">
					<td class="thumb">
					     <img src="images/<%=i.getPicture()%>" />
					     <a href=""><%=i.getName()%></a>
					</td>
					<td class="number"><%=i.getPrice() %></td>
					<td class="price" id="price_id_1">
					    <span><%=i.getPrice()*goods.get(i) %></span>
						<input type="hidden" value="" />
				    </td>
					<td class="number"><%=goods.get(i)%></td>
					<td class="delete"><a href="CartServlet?action=delete&id=<%=i.getId()%>" οnclick="delcfm();">删除</a></td>
				</tr>
				<% 
				         }
				%>
				<!--循环的结束-->


			</table>
			<div class="total">
				<span id="total">总计：<%=cart.getTotalPrice() %>￥</span>
			</div>
			<% 
			    }
			 %>
			<div class="button">
				<input type="submit" value="" />
			</div>
		</form>
	</div>
</body>
</html>

项目运行结果：

商品列表：

选择一个商品进入商品详情：

选择好数量，加入到购物车中：

查看购物车：



针对很多人要源码，我把源码上传了到CSDN上，大家自己下载，工作了有时候回复不及时。本来想要直接分



享的，可是最低需要设置一个积分，没办法，以后代码会放在GITHUB上。



地址：https://download.csdn.net/download/erlian1992/10393969


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