实现原理：从Action中返回JSON格式的字符串，在ajax中获取到data,并将其转换成js的JSON数据，然后遍历

注：亦可在Java代码就转换为JSON格式，使用JSONArrayjsonArray=JSONArray.fromObject(string)，写write(jsonArray.toString());这时在JS里就不需要使用eval()转换直接遍历

Struts.xml

<action name="myAjaxAction" class="myAction" method="myAjaxAction"><interceptor-ref name="mystack" /></action>
		

Action方法

public void myAjaxAction(){
		try{
			HttpServletResponse responses = ServletActionContext.getResponse();
			responses.setCharacterEncoding("utf-8");
			PrintWriter writer = responses.getWriter();
			//设置JSON数据，\"是转义符，实际内容为：[{name:"张三",age:12},{name:"李四",age:11},{name:"王五",age:13},{name:"小六",age:14}]；
			String string="[{name:\"张三\",{name:\"李四\",{name:\"王五\",{name:\"小六\",age:14}]";
			writer.write(string);
			writer.flush();
			writer.close();
		}catch (Exception e) {
			// TODO: handle exception
		}
	}

HTML

<input type="button" value="测试JSON" onclick="ajaxJson()"/> 

JS代码

function ajaxJson(){
	$.ajax({
        type:"post",url:"myAjaxAction.action",async:true,success:function(data) {
        	var obj=eval("("+data+")");//将数据转换成json类型
			for(var i in obj){//遍历Json数据 
			    alert("姓名:"+obj[i].name+" 年龄:"+obj[i].age );  
			}
        },error:function(e) {
          alert("验证失败!");
        }
      });
}