JSON（JavaScript Object Notation）一种简单的数据格式，比xml更轻巧。JSON是JavaScript原生格式，这意味着在JavaScript中处理JSON数据不需要任何特殊的API或工具包。
练习示例：
效果图：
首先要创建实体类User.java:
public class User {
Integer id;
String name;
String sex;
public User() {
super();
// TODO Auto-generated constructor stub
}
public User(Integer id, String name, String sex) {
super();
this.id = id;
this.name = name;
this.sex = sex;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
}
json .jsp
<body> <table border="1px" align="center"> <thead> <tr> <th>id号</th> <th>姓名</th> <th>性别</th> </tr> </thead> <tbody id="users"> </tbody> </table> </body>
<script type="text/javascript">
<!--
window.onload=function(){
//获取xhr对象
var xmlHttp = createXmlHttpRequest();
xmlHttp.onreadystatechange = function() {
//判断 服务器是否正确返回 相应信息
if (xmlHttp.readyState == 4) {
//接受数据
var jsonStr =xmlHttp.responseText;
var jsonEmps = eval("("+jsonStr+")");
display(jsonEmps);
}
}
////规定请求的类型
xmlHttp.open("GET", "./ListServlet?timeStamp="
+ new Date().getTime(), true);
//发送请求
xmlHttp.send(null);
}
function display(obj){
var users=document.getElementById("users");
for(var i=0;i<obj.length;i++){
//创建tr
var tr=document.createElement("tr");
//创建td
var td1=document.createElement("td");
var td2=document.createElement("td");
var td3=document.createElement("td");
//添加文本
td1.appendChild(document.createTextNode(obj[i].id));
td2.appendChild(document.createTextNode(obj[i].name));
td3.appendChild(document.createTextNode(obj[i].sex));
//添加到tr中
tr.appendChild(td1);
tr.appendChild(td2);
tr.appendChild(td3);
//添加到users中
users.appendChild(tr);
}
}
function createXmlHttpRequest(){
var xmlHttp;
try { //Firefox, Opera 8.0+, Safari
xmlHttp = new XMLHttpRequest();
} catch (e) {
try { //Internet Explorer
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
}
}
}
return xmlHttp;
}
//-->
</script>
最后是servlet
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
List<User> list=new ArrayList<User>();
for(int i=0;i<5;i++){
User user=new User(i,"ren"+i,"nv");
list.add(user);
}
String json=JSONArray.fromObject(list).toString();
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
out.print(json);
System.out.println("as");
}