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:
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