购物车（jsp servlet)

BookDao.java

package com.bhsi.dao;

import java.util.List;
import java.util.Map;

import com.hbsi.domain.Book;

public interface BookDao {
 
  
 public Book find(String id);
 
 public List<Book> getALL();
 
 
}

BookDaoImpl.java
package com.hbsi.dao.impl;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.bhsi.dao.BookDao;
import com.hbsi.domain.Book;
import com.hbsi.utils.DBManager;

public class BookDaoImpl implements BookDao{

 @Override
 public Book find(String id) {
  Connection conn = null;
  PreparedStatement st = null;
  ResultSet rs = null;

  try {
   conn = DBManager.getConnection();
   String sql = "select * from book where id=?";
   st = conn.prepareStatement(sql);

   st.setString(1, id);

   rs = st.executeQuery();
   if (rs.next()) {
    Book b = new Book();
    b.setId(rs.getString("id"));
    b.setName(rs.getString("name"));
    b.setPrice(rs.getDouble("price"));
    b.setAuthor(rs.getString("author"));
    b.setDescription(rs.getString("description"));
    
    return b;
   }
   return null;
  } catch (SQLException e) {
   throw new RuntimeException(e);
  } finally {
   DBManager.colseDb(conn, st, rs);
  }

 }

 
 @Override
 public List<Book> getALL() {
  Connection conn = null;
  PreparedStatement st = null;
  ResultSet rs = null;

  try {
   conn = DBManager.getConnection();
   String sql = "select * from book";
   st = conn.prepareStatement(sql);
   rs = st.executeQuery();
   List<Book> list = new ArrayList<Book>();
   while (rs.next()) {
    Book b = new Book();
    b.setId(rs.getString("id"));
    b.setName(rs.getString("name"));
    b.setPrice(rs.getFloat("price"));
    b.setAuthor(rs.getString("author"));
    b.setDescription(rs.getString("description"));

    list.add(b);
   }
   return list;
  } catch (Exception e) {
   throw new RuntimeException(e);
  } finally {
   DBManager.colseDb(conn, st, rs);
  }
 }

}

Book.java
package com.hbsi.domain;

import java.io.Serializable;

public class Book implements Serializable{
 
 /**
  *
  */
 private static final long serialVersionUID = 1L;
 private String id;
 private String name;
 private double price;
 private String author;
 private String description;
 public String getId() {
  return id;
 }
 public void setId(String 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 String getAuthor() {
  return author;
 }
 public void setAuthor(String author) {
  this.author = author;
 }
 public String getDescription() {
  return description;
 }
 public void setDescription(String description) {
  this.description = description;
 }
 
 

}

 Cart.java
package com.hbsi.domain;

import java.util.LinkedHashMap;
import java.util.Map;

//购物车
public class Cart {
 
 //private Map<String,Book> map = new LinkedHashMap<String, Book>();
 //用户会买一本书多本,会出现重复的书,要使用购物项,避免重复书出现。
 private Map<String,CartItem> map = new LinkedHashMap<String, CartItem>();
 private double price;  //总计
 
 public void add(Book book){
  //首先判断要买的书是否已经在购物车里
  CartItem  item = map.get(book.getId());
  if(item!=null){
   item.setQuantity(item.getQuantity()+1);
  }else{
   //第一次买这本书
   item = new CartItem();
   item.setBook(book);
   item.setQuantity(1);
   map.put(book.getId(),item);
  }
  
 }
 
 public Map<String, CartItem> getMap() {
  return map;
 }

 public void setMap(Map<String, CartItem> map) {
  this.map = map;
 }

 public double getPrice() {
  double totalprice =0;
  for(Map.Entry<String,CartItem> me: map.entrySet()){
   totalprice = totalprice+me.getValue().getPrice();
  }
  this.price=totalprice;
  return price;
 }

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

CartItem .java
package com.hbsi.domain;

//用于封装某本书,并表示这本书买了多少次
public class CartItem {
 
 private Book book;
 private int quantity;
 
 private double price; //小计

 public Book getBook() {
  return book;
 }

 public void setBook(Book book) {
  this.book = book;
 }

 public int getQuantity() {
  return quantity;
 }

 public void setQuantity(int quantity) {
  
  this.quantity = quantity;
  this.price = this.book.getPrice()*this.quantity;
 }

 public double getPrice() {
  return price;
 }

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

BusinessServiceImpl.java
package com.hbsi.service.impl;

import java.util.List;

import com.bhsi.dao.BookDao;
import com.hbsi.dao.impl.BookDaoImpl;
import com.hbsi.domain.Book;
import com.hbsi.domain.Cart;
import com.hbsi.domain.CartItem;
import com.hbsi.service.BusinessService;

public class BusinessServiceImpl implements BusinessService {
 
 BookDao dao = new BookDaoImpl();

 @Override
 public List<Book> getAllBook() {
  
  return dao.getALL();
 }

 @Override
 public void buyBook(String id, Cart cart) {
  Book book = dao.find(id);
  cart.add(book);
  
 }
 @Override
 public void updateCart(Cart cart, String bookid, String quantity) {
  CartItem item = cart.getMap().get(bookid);
  item.setQuantity(Integer.parseInt(quantity));
 } 
 @Override
 public void deleteCartItem(Cart cart, String id) {
  cart.getMap().remove(id);
 }
 @Override
 public void clearCart(Cart cart) {
  cart.getMap().clear();
 }
}

BusinessService.java
package com.hbsi.service;

import java.util.List;

import com.hbsi.domain.Book;
import com.hbsi.domain.Cart;

public interface BusinessService {
 
 //获取所有的书的服务
 public List<Book> getAllBook();
 //帮助用户完成书籍的购买
 public void buyBook(String id,Cart cart);
 //更新购物车中的书籍数量
 public void updateCart(Cart cart, String bookid, String quantity);
 //删除购物车中的书籍
 public void deleteCartItem(Cart cart, String id);
 //清空购物车中的书籍
 public void clearCart(Cart cart);
}

DBManager.java

package com.hbsi.utils;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import com.mysql.jdbc.Driver;

public class DBManager {
 
 private static String username;
 private static String password;
 private static String url;
 private static String driver;
 
 static{
  try{
   InputStream in = DBManager.class.getClassLoader().getResourceAsStream("db.properties");
   Properties prop = new Properties();
   prop.load(in);
   
   driver = prop.getProperty("driver");
   url = prop.getProperty("url");
   
   username = prop.getProperty("username");
   password = prop.getProperty("password");
   
   Class.forName(driver);
   
  }catch (Exception e) {
   throw new ExceptionInInitializerError(e);
  }
 }
 
 
 public static Connection getConnection() throws SQLException{
  return DriverManager.getConnection(url, username, password);
 }
 
 
 public static void colseDb(Connection conn,Statement st,ResultSet rs){
  
  if(rs!=null){
   try{
    rs.close();
   }catch (Exception e) {e.printStackTrace();}
    rs = null;
  }
  if(st!=null){
   try{
    st.close();
   }catch (Exception e) {e.printStackTrace();}
   st = null;
  }
  if(conn!=null){
   try{
    conn.close();
   }catch (Exception e) {e.printStackTrace();}
   conn = null;
  }
  
 }
 
 
}

BuyServlet.java

package com.hbsi.web.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.Cart;
import com.hbsi.domain.CartItem;
import com.hbsi.service.BusinessService;
import com.hbsi.service.impl.BusinessServiceImpl;

public class BuyServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  response.setContentType("text/html;charset=UTF-8");
  PrintWriter out = response.getWriter();
  
  String id = request.getParameter("id");
  
  Cart cart = (Cart) request.getSession().getAttribute("cart");
  if(cart==null){
   cart = new Cart();
   request.getSession().setAttribute("cart",cart);
  }
  
  BusinessServiceImpl service = new BusinessServiceImpl();
  service.buyBook(id,cart);
  
  //request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request, response);
  request.getRequestDispatcher("/listcart.jsp").forward(request, response);

 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doGet(request, response);
 }

}

ClearCartServlet.java

package com.hbsi.web.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.Cart;
import com.hbsi.service.impl.BusinessServiceImpl;

public class ClearCartServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  Cart cart = (Cart) request.getSession().getAttribute("cart");
  BusinessServiceImpl service = new BusinessServiceImpl();
  service.clearCart(cart);
  // request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request,
  // response);
  request.getRequestDispatcher("/listcart.jsp")
    .forward(request, response);
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doGet(request, response);
 }

}

DeleteBookServlet.java

package com.hbsi.web.controller;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.Cart;
import com.hbsi.service.impl.BusinessServiceImpl;

public class DeleteBookServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  String id = request.getParameter("id");

  Cart cart = (Cart) request.getSession().getAttribute("cart");
  BusinessServiceImpl service = new BusinessServiceImpl();
  service.deleteCartItem(cart, id);

  // request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request,
  // response);
  request.getRequestDispatcher("/listcart.jsp")
    .forward(request, response);

 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doGet(request, response);
 }

}

ListBookServlet.java

package com.hbsi.web.controller;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.Book;
import com.hbsi.service.BusinessService;
import com.hbsi.service.impl.BusinessServiceImpl;

public class ListBookServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  response.setContentType("text/html;charset=UTF-8");
  PrintWriter out = response.getWriter();

  BusinessService service = new BusinessServiceImpl();
  List<Book> list = service.getAllBook();
  request.setAttribute("books", list);
  // request.getRequestDispatcher("/WEB-INF/jsp/listbook.jsp").forward(request,response);
  request.getRequestDispatcher("/listbook.jsp")
    .forward(request, response);
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doGet(request, response);
 }
}

UpdateCartServlet.java

package com.hbsi.web.controller;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hbsi.domain.Cart;
import com.hbsi.service.BusinessService;
import com.hbsi.service.impl.BusinessServiceImpl;

public class UpdateCartServlet extends HttpServlet {

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  String bookid = request.getParameter("bookid");
  String quantity = request.getParameter("quantity");
  Cart cart = (Cart) request.getSession().getAttribute("cart");
  BusinessServiceImpl service = new BusinessServiceImpl();
  service.updateCart(cart, bookid, quantity);

  // request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request,
  // response);
  request.getRequestDispatcher("/listcart.jsp")
    .forward(request, response);
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doGet(request, response);
 }

}

listbook.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
   
    <title>显示所有的书</title>
   
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0">   
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->

  </head>
 
  <body style="text-align:center">
    <h2>我的书店</h2>
    <table border="1" width="80%">
      <tr>
        <td>编号</td>
        <td>书名</td>
        <td>作者</td>
        <td>价格</td>
        <td>描述</td>
        <td>操作</td>
      </tr>
     
      <c:forEach var="book" items="${books}">
      <tr>
        <td>${book.id}</td>
        <td>${book.name}</td>
        <td>${book.author}</td>
        <td>${book.price}</td>
        <td>${book.description}</td>
        <td>
          <a href="${pageContext.request.contextPath}/servlet/BuyServlet?id=${book.id}">购买</a>
        </td>
      </tr>
     
      </c:forEach>
          
    </table>
  
  </body>
</html>

listcart.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
   
    <title>购物车显示页面</title>
   
 <meta http-equiv="pragma" content="no-cache">
 <meta http-equiv="cache-control" content="no-cache">
 <meta http-equiv="expires" content="0">   
 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="This is my page">
 <!--
 <link rel="stylesheet" type="text/css" href="styles.css">
 -->
 <script>
     function doDelete(id){
      var b = window.confirm("您确定删除吗??");
      if(b){
       window.location.href="${pageContext.request.contextPath }/servlet/DeleteBookServlet?id="+id;
      }
     }
     
     function clearCart(){
      var b = window.confirm("您确定清空吗??");
      if(b){
       window.location.href="${pageContext.request.contextPath }/servlet/ClearCartServlet";
      }
     }
     
     function updateCart(input,bookid,oldvalue){
      var b = window.confirm("您确定修改吗??");
      if(b){
        var quantity = input.value;
        if(quantity==""){
         alert("请输入数字！！");
         input.value=oldvalue;
         return;
        }
        if(!quantity.match("\\d+")){
         alert("请输入数字!!");
         input.value=oldvalue;
         return;
        }
        if(quantity<1){
         alert("请输入有效数字!!");
         input.value=oldvalue;
         return;
        }
       
       
       
       window.location.href='${pageContext.request.contextPath}/servlet/UpdateCartServlet?bookid='+bookid+'&quantity='+quantity;
      }else{
       input.value=oldvalue;
      }
     }
    </script>
  </head>
 
 <body style="text-align:center">
    <h2>您购买了如下商品</h2>
    <table border="1" width="80%">
      <tr>
        <td>编号</td>
        <td>书名</td>
        <td>价格</td>
        <td>数量</td>
        <td>小计</td>
        <td>操作</td>
      </tr>
     
      <c:forEach  var="me" items="${cart.map}">
      <tr>
        <td>${me.key}</td>
        <td>${me.value.book.name}</td>
        <td>${me.value.book.price}</td>
        <td>
     <input type="text" value="${me.value.quantity}" onchange="updateCart(this,${me.key },${me.value.quantity})" style="width:35px;">
     </td>
        <td>${me.value.price}</td>
        <td>
          <a href="javascript:void(0)" onclick="doDelete(${me.key })">删除</a>
        </td>
      </tr>
      </c:forEach>
       <tr>
      <td><a href="javascript:void(0)" onclick="clearCart()">清空购物车</a></td>
      <td><a href="servlet/ListBookServlet">继续选书</a></td>
      <td colspan="2">总价</td>
      <td colspan="2">${cart.price }元</td>
     </tr>     
    </table>
  
  </body>
</html>