Ajax 简单购物车工程

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工程结构图：

index.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>Insert title here</title>
<script type="text/javascript" src="${pageContext.request.contextPath }/scripts/jquery.js">
</script><script type="text/javascript">$(function(){var isHasCart = "${sessionScope.sc==null}";if(isHasCart){$("#cartstatus").hide();}else{$("#cartstatus").show();$("#bookName").text("${sessionScope.sc.bookName}");$("#totalBookNumber").text("${sessionScope.sc.totalBookNumber}");$("#totalMoney").text("${sessionScope.sc.totalMoney}");}$("a").click(function(){$("#cartstatus").show();var url = this.href;var args = {"time":new Date()};$.getJSON(url,args,function(data){$("#bookName").text(data.bookName);$("#totalBookNumber").text(data.totalBookNumber);$("#totalMoney").text(data.totalMoney);});return false;});})
</script>
</head>
<body><div id="cartstatus">您已经将 <span id="bookName"></span> 添加到购物车中,购物车中共有 <span id="totalBookNumber"></span> 本，总钱数 <span id="totalMoney"></span> 元<br></div>Java     <a href="${pageContext.request.contextPath }/addToCart?id=Java&price=100">加入购物车</a><br>Oracle   <a href="${pageContext.request.contextPath }/addToCart?id=Oracle&price=200">加入购物车</a><br>Struts2  <a href="${pageContext.request.contextPath }/addToCart?id=Struts2&price=100">加入购物车</a><br></body>
</html>

AddToCart.java

import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;import com.trekiz.beans.ShoppingCart;/*** Servlet implementation class AddToCart*/
@WebServlet("/addToCart")
public class AddToCart extends HttpServlet {private static final long serialVersionUID = 1L;/*** @see HttpServlet#HttpServlet()*/public AddToCart() {super();// TODO Auto-generated constructor stub}/*** @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)*/protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request,response);}/*** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)*/protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {String bookName = request.getParameter("id");int price = Integer.parseInt(request.getParameter("price"));//获取购物车对象HttpSession session = request.getSession();ShoppingCart sc = (ShoppingCart) session.getAttribute("sc");if(sc==null){sc = new ShoppingCart();session.setAttribute("sc", sc);}sc.addToCart(bookName, price);//准备响应的json对象StringBuilder result = new StringBuilder();//若从服务端返回json字符串，则属性名必须使用双引号result.append("{").append("\"bookName\":\""+bookName+"\"").append(",").append("\"totalBookNumber\":"+sc.getTotalBookNumber()).append(",").append("\"totalMoney\":"+sc.getTotalMoney()).append("}");response.setContentType("text/javascript");response.getWriter().println(result.toString());}}

ShoppingCart.java

import java.util.HashMap;
import java.util.Map;public class ShoppingCart {private String bookName;private Map<String,ShoppingCartItem> items = new HashMap<String, ShoppingCartItem>();public void addToCart(String bookName, int price){this.bookName = bookName;if(items.containsKey(bookName)){ShoppingCartItem item = items.get(bookName);item.setNumber(item.getNumber()+1);}else{ShoppingCartItem item = new ShoppingCartItem();item.setBookName(bookName);item.setPrice(price);item.setNumber(1);items.put(bookName, item);}}public int getTotalBookNumber(){int total=0;for(ShoppingCartItem item : items.values()){total = total + item.getNumber();}return total;}public int getTotalMoney(){int money = 0;for(ShoppingCartItem item : items.values()){money = money + item.getPrice()*item.getNumber();}return money;}public String getBookName(){return this.bookName;}}

ShoppingCartItem.java


public class ShoppingCartItem {private int number;private String bookName;private int price;public int getNumber() {return number;}public void setNumber(int number) {this.number = number;}public String getBookName() {return bookName;}public void setBookName(String bookName) {this.bookName = bookName;}public int getPrice() {return price;}public void setPrice(int price) {this.price = price;}}

拼接json字符串时，在导入jackson jar后，可以使用如下两行代码，更简便

ObjectMapper mapper = new ObjectMapper();
String result = mapper.writeValueAsString(sc);

效果图：