Ajax学习笔记-购物车

发布时间：2020-12-16 01:43:35 所属栏目：百科来源：网络整理

导读：650) this.width=650;" src="http://img.jb51.cc/vcimg/static/loading.png" title="QQ截图20141009163718.png" alt="wKioL1Q2SYPRBh7ZAACQ5cOHFcE328.jpg" src="http://s3.51cto.com/wyfs02/M00/4B/F9/wKioL1Q2SYPRBh7ZAACQ5cOHFcE328.jpg"> %@pagelanguage

<%@pagelanguage="java"contentType="text/html;charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPEhtmlPUBLIC"-//W3C//DTDHTML4.01Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<metahttp-equiv="Content-Type"content="text/html;charset=UTF-8">
<title></title>
<scripttype="text/javascript"src="${pageContext.request.contextPath}/js/jquery-1.11.1.min.js"></script>
<scripttype="text/javascript">
	$(function(){
		//判断session里是否已经有shoppingCart
		varisHasCart="${sessionScope.shoppingCart==null}";
		//如果session里没有shoppingCart，说明是第一次来到这个页面
		if(isHasCart=="true"){
			$("#cartstatus").hide();
		}else{
			$("#cartstatus").show();
			$("#bookName").text("${sessionScope.shoppingCart.bookName}");
			$("#totalBookNum").text("${sessionScope.shoppingCart.totalBookNum}");
			$("#totalMoney").text("${sessionScope.shoppingCart.totalMoney}");
		}
		
		$("a").click(function(){
			$("#cartstatus").show();
			varurl=this.href;
			varargs={"time":newDate()};
			$.getJSON(url,args,function(data){
				$("#bookName").text(data.bookName);
				$("#totalBookNum").text(data.totalBookNum);
				$("#totalMoney").text(data.totalMoney);
			});
			returnfalse;
		});
	})
</script>
</head>
<body>
<!--
1.获取当前页面所有的a结点，并为每一个a结点都添加onclick响应事件，同时取消其默认行为。
2.准备发送ajax请求：url（a结点的href属性值）args（时间戳）
3.响应为一个JSON对象，包括：bookNametotalBookNumtotalMoney
4.把对应的属性添加到对应的位置
-->
<divid="cartstatus">
您已将<spanid="bookName"></span>加入到购物车中，购物车中的书有<spanid="totalBookNum"></span>本，总价是<spanid="totalMoney"></span>元
</div>
<br/>
Java<ahref="${pageContext.request.contextPath}/addToCart?id=Java&price=100">加入购物车</a>
<br/>
Oracle<ahref="${pageContext.request.contextPath}/addToCart?id=Oracle&price=150">加入购物车</a>
<br/>
Struts2<ahref="${pageContext.request.contextPath}/addToCart?id=Struts2&price=180">加入购物车</a>
<br/>
</body>
</html>

ShoppingCartItem.java

publicclassShoppingCartItem{
	privateintnumber;
	privateStringbookName;
	privateintprice;
	//...
}

ShoppingCart.java 购物车

publicclassShoppingCart{
	//key:书名value:ShoppingCartItem对象
	privateMap<String,ShoppingCartItem>items=newHashMap<String,ShoppingCartItem>();
	privateStringbookName;
	
	publicvoidaddToCart(StringbookName,intprice){
		this.bookName=bookName;
		if(items.containsKey(bookName)){
			ShoppingCartItemshoppingCartItem=items.get(bookName);
			shoppingCartItem.setNumber(shoppingCartItem.getNumber()+1);
		}else{
			ShoppingCartItemshoppingCartItem=newShoppingCartItem();
			shoppingCartItem.setBookName(bookName);
			shoppingCartItem.setNumber(1);
			shoppingCartItem.setPrice(price);
			items.put(bookName,shoppingCartItem);
		}
	}
	
	publicintgetTotalBookNum(){
		inttotal=0;
		for(ShoppingCartItemitem:items.values()){
			total+=item.getNumber();
		}
		returntotal;
	}
	
	publicintgetTotalMoney(){
		intmoney=0;
		for(ShoppingCartItemitem:items.values()){
			money+=item.getNumber()*item.getPrice();
		}
		returnmoney;
	}
	
	publicStringgetBookName(){
		returnbookName;
	}
}

addToCart.java servlet

		StringbookName=request.getParameter("id");
		intprice=Integer.parseInt(request.getParameter("price"));
		ShoppingCartshoppingCart=(ShoppingCart)request.getSession().getAttribute("shoppingCart");
		if(shoppingCart==null){
			shoppingCart=newShoppingCart();
			request.getSession().setAttribute("shoppingCart",shoppingCart);
		}
		shoppingCart.addToCart(bookName,price);
		StringBuilderresult=newStringBuilder();
		result.append("{")
		//必须用双引号
		.append(""bookName":""+bookName+""")
		.append(",")
		.append(""totalBookNum":"+shoppingCart.getTotalBookNum())
		.append(",")
		.append(""totalMoney":"+shoppingCart.getTotalMoney())
		.append("}");
		
		response.setContentType("text/javascript");
		response.getWriter().print(result.toString());

补充：Jackson的使用

publicclassCustomer{
	privateintid;
	privateStringname;

	publicintgetId(){
		returnid;
	}

	publicvoidsetId(intid){
		this.id=id;
	}

	publicStringgetName(){
		returnname;
	}

	publicvoidsetName(Stringname){
		this.name=name;
	}
	
	publicStringgetCity(){
		return"北京";
	}
	//忽略一个getter属性
	@JsonIgnore
	publicStringgetBirth(){
		return"1990-12-31";
	}

	publicCustomer(intid,Stringname){
		super();
		this.id=id;
		this.name=name;
	}

	publicstaticvoidmain(String[]args)throwsJsonGenerationException,JsonMappingException,IOException{
		ObjectMappermapper=newObjectMapper();
		Customercustomer=newCustomer(0,"umgsai");
		StringjsonString=mapper.writeValueAsString(customer);
		System.out.println(jsonString);
		//Jackson使用getter方法来定位JSON对象的属性
		//{"name":"umgsai","id":0,"city":"北京"}
	}
}

本例使用的Jar包是jackson-all-1.7.6.jar

教程中加的是下面三个包

jackson-annotation-2.2.2.jar

jackson-core-2.2.2.jar

jackson-databind-2.2.2.jar

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（编辑：李大同）

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