简陋的图书商城应用（无结算页面）

时间：2016-04-09 21:54:12 阅读：295 评论：0 收藏：0 [点我收藏+]

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WEB应用总览

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1.建立好相应的包，从底层开始开发

　　domain包添加Book类

package cn.itcast.domain;

public class Book {
    private String id;
    private String name;
    private String author;
    private Double price;
    private String description;
    
    public Book() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Book(String id, String name, String author, Double price,
            String description) {
        super();
        this.id = id;
        this.name = name;
        this.author = author;
        this.price = price;
        this.description = 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 String getAuthor() {
        return author;
    }
    public void setAuthor(String author) {
        this.author = author;
    }
    public Double getPrice() {
        return price;
    }
    public void setPrice(Double price) {
        this.price = price;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    
}

2 用一个类模拟数据库，map保存书本

package cn.itcast.DB;

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

import cn.itcast.domain.Book;

//代表数据库
public class DB {
    private static Map map=new LinkedHashMap();
    static{
        map.put("1", new Book("1","javaweb", "张三", 20.0, "一本好书"));
        map.put("2", new Book("2","jsp", "李四", 50.0, "一本好书"));
        map.put("3", new Book("3","html", "王五", 40.0, "一本好书"));
        map.put("4", new Book("4","Spring", "张韧", 60.0, "一本好书"));
        map.put("5", new Book("5","Ajax", "张文博", 20.0, "一本好书"));
        map.put("6", new Book("6","struts", "周利强", 40.0, "一本好书"));
    }
    public static Map getAll(){
        return map;
        
    }
}

3 操作数据库的Dao类

package cn.itcast.dao;

import java.util.Map;

import cn.itcast.DB.DB;
import cn.itcast.domain.Book;

public class BookDao {
    public Map getAll(){
        return DB.getAll();
        
    }
    public Book find(String id){
        return (Book) DB.getAll().get(id);
        }
    
}

4 初步写出业务层

package cn.itcast.service;

import java.util.Map;

import cn.itcast.dao.BookDao;
import cn.itcast.domain.Book;
import cn.itcast.domain.Cart;

public class BusinessService {
    private BookDao dao=new BookDao();
    public Map getAllBook(){          
        return dao.getAll();
        
    }
    public Book findBook(String id){
        return dao.find(id);
        
    }

5 图书商城首页

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
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>图书商城</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">
    <a style="font-size:50px"    href="${pageContext.request.contextPath }/servlet/ListBookServlet">浏览书籍</a> <br>
  </body>
</html>

　　6 由上可知，点击首页的浏览，跳转到一个WBE层的ListBookServlet

public class ListBookServlet extends HttpServlet {

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

        BusinessService service=new BusinessService(); //WEB层统一调用业务层方法
        Map map=service.getAllBook();
        //获取数据库，并转发到一个jsp页面
        request.setAttribute("map", map);
        request.getRequestDispatcher("/WEB-INF/jsp/listbook.jsp").forward(request, response);
    }

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

        doGet(request, response);
    }

}

7 在WEB-INF下新建目录jsp，再在jsp中新建 listbook.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>    <%-- 导入jstl包，将c.tld标签库引入 --%>
<%
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>书籍列表</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">
   <h1>书籍列表</h1>
<center> <table  style="align: center" border="1"  width="80%" >
           <tr >
               <td >书名</td>
               <td>作者</td>
               <td>售价</td>
               <td>描述</td>
               <td>操作</td>
           </tr>
           <c:forEach var="entry" items="${map }">  <%-- JSTL中forEach标签，遍历map --%>
               <tr>
               <td>${entry.value.name} </td>
               <td>${entry.value.author}</td>
               <td>${entry.value.price}</td>
               <td>${entry.value.description}</td>
               <td>
               <a href="${pageContext.request.contextPath}/servlet/BuyServlet?id=${entry.value.id}" target="_blank">购买</a>
               </td>
               </tr>
           </c:forEach>    
  
</center>
  </body>
</html>

发布到服务器测试成功后接着完善功能

8 <a href="${pageContext.request.contextPath}/servlet/BuyServlet?id=${entry.value.id}" target="_blank">购买</a>

将要买的书的id发送到BuyServlet

所以我们准备WEB层新建BuyServlet

但此时有一个疑问，买的商品要放到哪里呢？正确的做法是买到购物车中，再结算，而购物车的每个购物项目都有自己相应的数目

so，先在domain中建立购物车Cart和购物项CartItem类。

package cn.itcast.domain;

import java.util.Map;

//存放书的购物项
public class CartItem {
    private Book book;  //书
    private int quantity;   //书的数量
    private double price;     //购物项的总价
    public Book getBook() {
        return book;
    }
    public void setBook(Book book) {
        this.book = book;
    }
    public int getQuantity() {
        return quantity;
    }
    //一旦数量改变，购物项的总价就改变
    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;
    }
    
}

package cn.itcast.domain;

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

//代表购物车
public class Cart {
    private Map<String,CartItem> map=new LinkedHashMap();
    private double price; //购物车总价
    public Map<String, CartItem> getMap() {
        return map;
    }
    public void setMap(Map<String, CartItem> map) {
        this.map = map;
    }
    //购物车总价为map中存放的所有购物项总价之和
    public double getPrice() {
        double totalprice=0;
        for(Map.Entry<String, CartItem> entry:map.entrySet()){
            CartItem item=entry.getValue();
            totalprice+=item.getPrice();
        }
        this.price=totalprice;
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    //每增加一本书，购物项中对应的书的数量加一
    public void add(Book book){
        CartItem item=map.get(book.getId());
        if(item==null){
            item =new CartItem ();
            item.setBook(book);
            item.setQuantity(1);
            map.put(book.getId(), item);
        }
        else{
            item.setQuantity(item.getQuantity()+1);
        }
    }
    
}

9 这时候我们再来新建BuyServlet

package cn.itcast.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 cn.itcast.domain.Book;
import cn.itcast.domain.Cart;
import cn.itcast.service.BusinessService;

public class BuyServlet extends HttpServlet {

    
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //根据id得到相应的书
        String id=request.getParameter("id");
        BusinessService service=new BusinessService();
        Book book=service.findBook(id);
        
        //得到购物车，将车加到购物车
        //购物车存在Session中
        Cart cart=(Cart) request.getSession().getAttribute("cart");
        if(cart==null){
            cart=new Cart();
            request.getSession().setAttribute("cart", cart);
        }
        cart.add(book);
        //转发到listcart.jsp，此处有瑕疵，刷新一次购买一次
        request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request, response);
    }

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

    doGet(request, response);
    }

}

此处应该用重定向（或其他方法？）。。避免刷新一次购买一次，日后改

10 jsp文件夹中新建

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>   <%-- 导入jstl包，将c.tld标签库引入 --%>
<%
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>购物车页面</title>
    <script type="text/javascript">
        //友好提示删除
         function deleteitem(id){
            var b=window.confirm("确认删除吗?");
        if(b){
        window.location.href="${pageContext.request.contextPath }/servlet/DeleteItemServlet?id="+id;
        }    
        }
        //友好提示清空
         function clearcart(){
            var b=window.confirm("确认清空吗?");
        if(b){
        window.location.href="${pageContext.request.contextPath }/servlet/ClearCartServlet";
        }    
        }
        
        //修改数量功能
        function changeQuantity(input,id,oldvalue){
            var quantity=input.value;
            //检查用户输入
            if(isNaN(quantity)||quantity<0){
                alert("请输入正整数");
                input.value=oldvalue;
                return;
            }  

        var b=window.confirm("确认修改数量吗?");
        if(b){
        window.location.href="${pageContext.request.contextPath }/servlet/ChangeQuantityServlet?id="+id + "&quantity="+quantity;
        
                
        }    
        
        }
        
        
    </script>
    

  </head>
  
   <body style="text-align: center">
   <h1>购物车列表</h1>
   <%-- jstl标签库if --%>
   <c:if test="${empty(cart.map)}">您没有购买任何物品</c:if>
   <c:if test="${!empty(cart.map)}">
   <table  width="80%" border="1" >
           <tr >
               <td>书名</td>
               <td>作者</td>
               <td>单价</td>
               <td>数量</td>
               <td>小计</td>
               <td>操作</td>
           </tr>
           <c:forEach var="entry" items="${ cart.map}">
               <tr>
               <td>${entry.value.book.name} </td>
               <td>${entry.value.book.author}</td>
               <td>${entry.value.book.price}</td>
               <td><input type="text" name="quantity" value="${entry.value.quantity}" style="width:30px" onchange="changeQuantity(this,${entry.value.book.id},${entry.value.quantity})"></td>
               <td>${entry.value.price}</td>
               <td>
               <a href="javascript:void(0)" onclick="deleteitem(${entry.key})" >删除</a>
               
               </td>
               </tr>
           </c:forEach>
           <tr>
                <td colspan="3">总价</td>
                <td colspan="2">${cart.price}元</td>
                <td colspan="1"><a href="javascript:clearcart()">清空购物车</a></td>
           </tr>    
   </table>
   </c:if>
  </body>
</html>

11 再写相应的Servelet之前，要把业务层增加功能

package cn.itcast.service;

import java.util.Map;

import cn.itcast.dao.BookDao;
import cn.itcast.domain.Book;
import cn.itcast.domain.Cart;

public class BusinessService {
    private BookDao dao=new BookDao();
    public Map getAllBook(){
        return dao.getAll();
        
    }
    public Book findBook(String id){
        return dao.find(id);
        
    }
    //删除购物车中购物项目
    public void deleteCartItem(String id, Cart cart) {
        // TODO Auto-generated method stub
        cart.getMap().remove(id);
    }
    //清空购物车
    public void cleatCart(Cart cart) {
        // TODO Auto-generated method stub
        cart.getMap().clear();
    }
    //更改购物项数目
    public void changeItemQuantity(String id, int quantity, Cart cart) {
        // TODO Auto-generated method stub
        cart.getMap().get(id).setQuantity(quantity);
    }
    
    
}

12写相应的Servelet

ackage cn.itcast.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 cn.itcast.domain.Book;
import cn.itcast.domain.Cart;
import cn.itcast.service.BusinessService;

public class DeleteItemServlet extends HttpServlet {

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

        String id=request.getParameter("id");
        BusinessService service=new BusinessService();
        Cart cart=(Cart) request.getSession().getAttribute("cart");
        service.deleteCartItem(id,cart);
        
        //删除后跳回购物车
        request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request, response);
    }

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

        doGet(request, response);
    }

}

package cn.itcast.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 cn.itcast.domain.Cart;
import cn.itcast.service.BusinessService;

public class ClearCartServlet extends HttpServlet {

    
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        BusinessService service=new BusinessService();
        Cart cart=(Cart) request.getSession().getAttribute("cart");
        service.cleatCart(cart);
        request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request, response);
        
    }

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

        doGet(request, response);
    }

}

package cn.itcast.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 cn.itcast.domain.Cart;
import cn.itcast.service.BusinessService;

public class ChangeQuantityServlet extends HttpServlet {

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

        String id=request.getParameter("id");
        int quantity=Integer.parseInt(request.getParameter("quantity"));
        
        BusinessService service=new BusinessService();
        Cart cart=(Cart) request.getSession().getAttribute("cart");
        service.changeItemQuantity(id,quantity,cart);
        request.getRequestDispatcher("/WEB-INF/jsp/listcart.jsp").forward(request, response);
    }

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

    doGet(request, response);
    }

}

发布效果

技术分享

点击几次购买

技术分享

清空

技术分享

修改数量

技术分享

总结：没有解决刷新又购买一次和又删除一次的问题

　　　界面功能太少

　　　没有对用户输入进行用java代码校正。

简陋的图书商城应用（无结算页面）

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原文地址：http://www.cnblogs.com/xurui1995/p/5372599.html

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