一个Json例子

servlet ：生成股票ID 和 price 弄成JSON的字符串传给jsp

JSP 自动刷新（异步请求）处理JSON字符串

servlet：

package web;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

public class Quoto extends HttpServlet {
    
    public void service(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        Random r = new Random();
        
        String stockName="s"+r.nextInt(999);
        double price = r.nextDouble()*100;
        Stock stock = new Stock();
        stock.setId(stockName);
        stock.setPrice(price);
        JSONObject json = JSONObject.fromObject(stock);
        String str =  json.toString();
        System.out.print(str);
        out.println(str);
        out.close();
    }

}

JSP：

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<html>
<head>
	<title>Insert title here</title>
	<style>
		#d1{
			width:400px;
			height:200px;
			border:1px solid black;
			margin-left:400px;
			margin-top:60px;
		}
		
	</style>
	<script type="text/javascript" src="js/prototype1.6.js"></script>
	<script type="text/javascript">
		function getXmlHttpRequest(){
		var xmlHttpRequest = null;
     if ((typeof XMLHttpRequest) != 'undefined') 
     {
     	//非ie浏览器
      xmlHttpRequest = new XMLHttpRequest();
     }else {
     //ie浏览器
     xmlHttpRequest = 
     new ActiveXObject('Microsoft.XMLHttp');
     }
     return xmlHttpRequest;
	}	
		var taskId;
		function allquoto(){
			if($("b1").value=="stop"){
				stopQuoto();
			}else if($("b1").value=="start"){
				quoto();
			}
		}
		function quoto(){
			taskId = setInterval(getPrice,500);
			$("b1").value="stop";
		}
		function stopQuoto(){
			clearInterval(taskId);
			$("b1").value="start";
		}
		function getPrice(){
			var xmlReq = getXmlHttpRequest();
			xmlReq.open('post','quoto',true);
			xmlReq.setRequestHeader("Content-Type",
        	"application/x-www-form-urlencoded");
        	xmlReq.onreadystatechange=function(){
        		//s10010,10
        		if(xmlReq.readyState == 4){
        			var rsTxt = xmlReq.responseText;
        			//alert(rsTxt);
        			var stock = rsTxt.evalJSON();
        			$('d1').innerHTML=stock.id+":  "+stock.price;
        		}
        	}
        	xmlReq.send(null);
		}
	</script>
</head>
<body style="font-size:20pt;" onload="quoto();">
	<div id="d1">
	</div>
	<input type="button" id="b1" value="stop" style="margin-left:400px;" onclick="allquoto();"/>
</body>
</html>

posted on 2015-09-19 16:43 编世界阅读(582) 评论(0) 编辑收藏举报