问题所在：
当我们想让应用层和http之间的所有接口都采用json，这样，客户端代码就可以纯碎用javascript的对象来编写，服务器打啊也可以纯粹的用Java的对象来编写。
我们使用的是post请求的方法，有些不同于get的方法！
客户端html代码：
<html>
<head>
<title>Hello Ajax version 5a</title>
<style type='text/css'>
* { font-family: Tahoma, Arial, sans-serif; }
#helloTitle{ color: #48f; }
.sidebar{
background-color: #adf;
color: navy;
border: solid blue 1px;
width: 180px;
height: 200px;
padding: 2px;
margin: 3px;
float: left;
}
</style>
<script type='text/javascript' src='prototype.js'></script>
<script type='text/javascript' src='json.js'></script>
<script type='text/javascript'>
window.onload=function(){
$('helloBtn').onclick=function(){
var name=$('helloTxt').value;
new Ajax.Request(
"hello5a.jsp",
{
postBody:JSON.stringify({name:name}),
onComplete:function(xhr){
var responseObj=JSON.parse(xhr.responseText);
update(responseObj);
}
}
);
}
}
function update(obj){
$('helloTitle').innerHTML="<h1>Hello, <b><i>"+obj.name+"</i></b></h1>";
var likesHTML='<h5>'+obj.initial+' likes...</h5><hr/>';
for (var i=0;i<obj.likes.length;i++){
likesHTML+=obj.likes[i]+"<br/>";
}
$('likesList').innerHTML=likesHTML;
var recipeHTML='<h5>'+obj.initial+'\'s favourite recipe</h5>';
for (key in obj.ingredients){
recipeHTML+=key+" : "+obj.ingredients[key]+"<br/>";
}
$('ingrList').innerHTML=recipeHTML;
}
</script>
</head>
<body>
<div id='likesList' class='sidebar'>
<h5>Likes</h5><hr/>
</div>
<div id='ingrList' class='sidebar'>
<h5>Ingredients</h5><hr/>
</div>
<div>
<div id='helloTitle'>
<h1>Hello, stranger</h1>
</div>
<p>Please introduce yourself by entering your name in the box below</p>
<input type='text' size='24' id='helloTxt'></input> <button id='helloBtn'>Submit</button>
</div>
</body>
</html>
jsp代码：
<jsp:directive.page contentType="application/javascript" import="java.util.*,net.sf.json.*"/>
<%
//read the request body
String json=request.getReader().readLine(); //读取post请求主体
JSONObject jsonObj=new JSONObject(json);//解析json字符串
String name=(String)(jsonObj.get("name"));//读取解析后的对象
jsonObj.put("initial",name.substring(0,1).toUpperCase()); //添加新的值
String[] likes=new String[]{ "JavaScript", "Skiing", "Apple Pie" };
jsonObj.put("likes",likes);
Map ingredients=new HashMap();
ingredients.put("apples","3kg");
ingredients.put("sugar","1kg");
ingredients.put("pastry","2.4kg");
ingredients.put("bestEaten","outdoors");
jsonObj.put("ingredients",ingredients);
%><%=jsonObj%>
<!--以json的形式输出对象-->
另外我们还要用到包装集：
prototype.js和json.js
效果如下：
