json2.js是一个著名开源js库,提供了json的序列化和反序列化方法JSON.stringify：L353：把Json对象转换成字符串    JSON.parse：    L400：把字符串转成Json对象    http://www.json.org/                有    JavaScript:                    JSON.                json2.js.                clarinet.                Oboe.js.    

// 参考：XMLHttpRequest 对象                                        // http://www.w3school.com.cn/xml/xml_http.asp                                        xmlhttp = null;                                        if (window.XMLHttpRequest) {// code for all new browsers                                            xmlhttp = new XMLHttpRequest();                                    } else if (window.ActiveXObject) {// code for IE5 and IE6                                            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");                                    }                                        function ajaxRequest(url, param, callBackFunction) {                                            try {                                                                                    if (xmlhttp != null) {                                            var sUrl = url + ‘?date=‘ + new Date();                                        var oRequest = new XMLHttpRequest();                                        oRequest.onreadystatechange = function() {                                            if (oRequest.readyState == 4) {                                            callBackFunction(oRequest);                                    }                                    };                                                                                oRequest.open(‘POST‘, sUrl);                                        oRequest.setRequestHeader("Content-Type", "application/json");                                        oRequest.send(param);                                    }                                    } catch (e) {                                                                                }                                    }                                            

<script type="text/javascript" src="js/ajaxUtil.js"></script><script type="text/javascript" src="js/json2.js"></script><script type="text/javascript">    function checkuser(o) {        var url = "testjson"        var obj = {            "uname" : o.value        }        // 借助json2.js：Json对象→字符串,以便发送        var params = JSON.stringify(obj);        // 借助ajaxUtil.js：发送Ajax请求        ajaxRequest(url, params, ajaxCallBack);    }    // Ajax回调函数    function ajaxCallBack(oRequest) {        // 借助json2.js：字符串→Json对象，以便解析        var obj1 = JSON.parse(oRequest.responseText);        document.getElementById("msgdiv").innerHTML = obj1.msg1;    }</script>

    <p id="msgdiv"></p>    <s:form action="" name="test" method="post">        <s:textfield name="uname" onblur="checkuser(this)" />        <s:submit></s:submit>    </s:form>

<?xml version="1.0" encoding="UTF-8" ?>                                    <!DOCTYPE struts PUBLIC                                        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"                                    "http://struts.apache.org/dtds/struts-2.3.dtd"><struts>    <constant name="struts.enable.DynamicMethodInvocation" value="true" />    <constant name="struts.devMode" value="true" />    <constant name="struts.configuration.xml.reload" value="true" />    <!-- 不再继承struts-default，而是json-default -->    <package name="p1" namespace="/" extends="json-default">        <action name="testjson" class="org.ah.s2.C1">            <!-- 配置json拦截器，在struts2-json-plugin-2.3.20.jar中 -->            <interceptor-ref name="json" />            <result type="json">                <!-- root:固定值，返回给客户端的对象 -->                <!-- data：Action中的一个属性 -->                <param name="root">data</param>                <!-- 当返回结果有空值时，不包含进来 -->                <!-- 这里AhJsonBean.msg2不包含进来 -->                <param name="excludeNullProperties">true</param>            </result>        </action>    </package></struts>

package org.ah.s2;/** * Json用的Java Bean */public class AhJsonBean {    private String msg1;    private String msg2;    public String getMsg1() {        return msg1;    }    public void setMsg1(String msg1) {        this.msg1 = msg1;    }    public String getMsg2() {        return msg2;    }    public void setMsg2(String msg2) {        this.msg2 = msg2;    }}

package org.ah.s2;import com.opensymphony.xwork2.ActionSupport;public class C1 extends ActionSupport {    private String uname;    // -----------------------------    public String getUname() {        return uname;    }    public void setUname(String uname) {        this.uname = uname;    }    // -----------------------------    // <param name="root">data</param>    // 不需要setter，需要getter，需要new    private AhJsonBean data;    public AhJsonBean getData() {        return data;    }    // -----------------------------    @Override    public String execute() throws Exception {        // 需要new一个Json的对象        data = http://www.mamicode.com/new AhJsonBean();        if ("admin".equals(uname)) {            data.setMsg1("这是管理员");        } else {            data.setMsg1("OK!");        }        return ActionSupport.SUCCESS;    }}