小项目

(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 TransferSource Server         : MySQL50Source Server Version : 50067Source Host           : localhost:3306Source Database       : shoppingTarget Server Type    : MYSQLTarget Server Version : 50067File Encoding         : 65001Date: 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connprivate 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;}@Overridepublic int hashCode() {return this.getId()+this.getName().hashCode();}@Overridepublic 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;}}@Overridepublic 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());}}

      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;}}}

      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,deleteprivate 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 stubdoPost(request, response);}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubresponse.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>

      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>

      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>