json

准备一个简单Person类
json1.jsp 测试结果两次alert
json2.jsp json2首先准备好一个servlet向浏览器发送字符串
json3.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'json2.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
<script type="text/javascript">
function createXMLHttpRequest() {
    try {
        return new XMLHttpRequest();//大多数浏览器
    } catch (e) {
        try {
            return ActvieXObject("Msxml2.XMLHTTP");//IE6.0
        } catch (e) {
            try {
                return ActvieXObject("Microsoft.XMLHTTP");//IE5.5及更早版本    
            } catch (e) {
                alert("哥们儿，您用的是什么浏览器啊？");
                throw e;
            }
        }
    }
}
window.onload = function() {
    // 获取btn元素
    var btn = document.getElementById("btn");
    btn.onclick = function() {//给按钮的点击事件上添加监听
        // 使用ajax得到服务器端响应，把结果显示到h3中
        //1. 得到request
        var xmlHttp = createXMLHttpRequest();
        //2. 连接
        xmlHttp.open("GET", "<c:url value='/AServlet'/>", true);
        //3. 发送
        xmlHttp.send(null);
        //4. 给xmlHttp的状态改变事件上添加监听
        xmlHttp.onreadystatechange = function() {
            //双重判断
            if(xmlHttp.readyState == 4 && xmlHttp.status == 200) {
                var text = xmlHttp.responseText;//它是一个json串
                // 执行json串
                var person = eval("(" + text + ")");
                var s = person.name + ", " + person.age + ", " + person.sex;
                document.getElementById("h3").innerHTML = s;
            }
        };
    };
};
</script>
  </head>
  
  <body>
  <%-- 点击按钮后，把服务器响应的数据显示到h3元素中 --%>
<button id="btn">点击这里</button>
<h1>JSON之HelloWorld</h1>
<h3 id="h3"></h3>

  </body>
</html>
json

JsonObject
