index.jsp页面
<%@ 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>
<!--
1.获取当前页面的所有的a节点，并为每一个a节点都添加onclick 响应函数，同时取消其默认行为
2.准备发送Ajax请求：url（a节点的href属性值）；args 时间戳
3.响应为一个JSON对象，包括：bookName totalBookNumber totalMoney
4.把对应的属性添加到对应的位置
-->
<script type="text/javascript" src="${pageContext.request.contextPath }/script/jquery.js"></script>
<script type="text/javascript">
$(function(){
var isHasCart = "${sessionScope.sc == null}";
if(isHasCart == "true"){
$("#status").hide();
}else {
$("#status").show();
//这里的sc是ShoppingCart的对象他会去调用sc.属性对应的get方法
$("#bookName").text("${sessionScope.sc.bookName}");
$("#totalNumber").text("${sessionScope.sc.totalNumber}");
$("#totalMoney").text("${sessionScope.sc.totalMoney}");
}
$("a").click(function(){
//显示指定的选择器
$("#status").show();
var url = this.href;
var args = {"time":new Date()};
$.getJSON(url, args, function(data){
$("#bookName").text(data.bookName);
$("#totalNumber").text(data.totalNumber);
$("#totalMoney").text(data.totalMoney);
});
return false;
});
});
</script>
</head>
<body>
<div id="status">
您已经将 <span id="bookName"></span>
加入到购物车，购物车中的书有 <span id="totalNumber"></span> 本，
总价格 <span id="totalMoney"></span> 元。
<br><br>
</div>
Java <a href="${pageContext.request.contextPath}/addToCart?id=Java&price=150">加入购物车</a>
<br><br>
Oracle <a href="${pageContext.request.contextPath }/addToCart?id=Oracle&price=200">加入购物车</a>
<br><br>
Struts2 <a href="${pageContext.request.contextPath }/addToCart?id=Struts2&price=100">加入购物车</a>
<br><br>
</body>
</html>
//SERVLET类
package com.ajax.app.servlet;
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.ajax.beans.ShoppingCart;
import com.fasterxml.jackson.databind.ObjectMapper;
@WebServlet("/addToCart")//这里这样写注解后就不用再web.xml中配置servlet了
public class AddToCartServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.获取请求参数：id , price
String bookName = request.getParameter("id");
int price = Integer.parseInt(request.getParameter("price"));
//2.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);
}
//3.把点击的选项加入到购物车中
sc.addToCart(bookName, price);
//4.准备响应的JSON对象:{"bookName":"","totalNumber":1，"totalMoney":1}
//这里的\"相当于一个' 但是这里不能写'
/* StringBuilder result = new StringBuilder();
result.append("{")
.append("\"bookName\":\""+bookName+"\"")
.append(",")
.append("\"totalNumber\":"+sc.getTotalNumber())
.append(",")
.append("\"totalMoney\":"+sc.getTotalMoney())
.append("}");
response.setContentType("text/javascript");
response.getWriter().print(result.toString());*/
ObjectMapper mapper = new ObjectMapper();
response.setContentType("text/javascript");
System.out.println(mapper.writeValueAsString(sc));
//响应ShoppingCart对象的JSON字符串
response.getWriter().print(mapper.writeValueAsString(sc));
}
}
//ShoppingCart类
package com.ajax.beans;
import java.util.HashMap;
import java.util.Map;
public class ShoppingCart {
//存放shoppingcartItem 的键 书名：值
private Map<String, ShoppingCartItem> items = new HashMap<>();
private String bookName;
public void addToCart(String bookName, int price){
this.bookName = bookName;
if(items.containsKey(bookName)){
ShoppingCartItem item = items.get(bookName);
item.setNumber(item.getNumber() + 1);
item.setPrice(item.getPrice()+price);
}else {
ShoppingCartItem item = new ShoppingCartItem();
item.setBookName(bookName);
item.setPrice(price);
item.setNumber(1);
items.put(bookName, item);
}
}
public int getTotalNumber(){
int total = 0;
for(ShoppingCartItem item: items.values()){
total += item.getNumber();
}
return total;
}
public int getTotalMoney(){
int money = 0;
for(ShoppingCartItem item: items.values()){
money += item.getPrice();
}
return money;
}
public String getBookName() {
return bookName;
}
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