这里有两个例子，一个是关于登录验证的，一个是异步加载数据的
1、regist.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>"> <title>My JSP 'regist.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" src="js/jquery-1.11.0.min.js"></script>
<script type="text/javascript">
$(function(){
$("#username").blur(function(){
$.ajax({
url:"checkUsername",
data:{"name":$("#username").val()},
success:function(data){
//alert(data);
var src = eval("("+data+")");
$("#sty").html(src.msg);
}
});
}); $(":button").click(function(){
$.ajax({
url:"findAll",
success:function(data){
$("tr").remove("tr:not(:eq(0))");
//alert(data);
var src = eval("("+data+")");
var table = $("table");
for(var i=0;i<src.length;i++){
//alert(src[i].name);
var tr = $("<tr></tr>");
var cell1 = $("<td>"+src[i].name+"</td>");
var cell2 = $("<td>"+src[i].sex+"</td>");
var cell3 = $("<td>"+src[i].age+"</td>");
cell1.appendTo(tr);
cell2.appendTo(tr);
cell3.appendTo(tr);
tr.appendTo(table);
}
}
});
}); });
</script> </head> <body>
<form action="registAction">
用户名:<input type="text" name="username" id="username"/><span id="sty"></span><br/>
密码:<input type="password" name="pwd" id="pwd"/><br/>
<input type="submit" value="注册"/>
</form>
<input type="button" value="查看全部"/><br/>
<table>
<tr>
<td>姓名</td>
<td>性别</td>
<td>年龄</td>
</tr>
</table>
</body>
</html>
2、导入JSON的必须包
3、CheckUsername.java
package com.cn.servlet; import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import net.sf.json.JSONObject; public class CheckUsername extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter(); String username = request.getParameter("name"); /*
* json格式
* {"name":"jack","age":"18"}
*/
//String msg = ""; //创建json对象
JSONObject job = new JSONObject(); if(username.equals("jack")){
//msg = "{\"msg\":\"当前用户已存在不可注册\"}";
job.put("msg", "当前用户已存在不可注册");
}else{
//msg = "{\"msg\":\"当前用户可注册\"}";
job.put("msg", "当前用户可注册");
} //out.print(msg);
out.print(job);
out.flush();
out.close();
} }
4、User.java
package com.cn.pojo;
public class User {
private String name;
private String sex;
private int age;
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;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public User() {
super();
// TODO Auto-generated constructor stub
}
public User(String name, String sex, int age) {
super();
this.name = name;
this.sex = sex;
this.age = age;
}
}
5、FindAll.java
package com.cn.servlet; import java.io.IOException;
import java.io.PrintWriter; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; import net.sf.json.JSONArray;
import net.sf.json.JSONObject; public class FindAll extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { this.doPost(request, response);
} public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter(); //json数组
//[{"name":"jack","sex":"男","age":"18"},{"name":"lily","sex":"女","age":"17"},{"name":"tom","sex":"男","age":"18"}] //json对象
JSONObject obj1 = new JSONObject();
obj1.put("name", "jack");
obj1.put("sex", "男");
obj1.put("age", "18"); JSONObject obj2 = new JSONObject();
obj2.put("name", "lily");
obj2.put("sex", "女");
obj2.put("age", "17"); JSONObject obj3 = new JSONObject();
obj3.put("name", "tom");
obj3.put("sex", "男");
obj3.put("age", "18"); //创建json数组
JSONArray ja = new JSONArray();
ja.add(obj1);
ja.add(obj2);
ja.add(obj3); out.print(ja);
out.flush();
out.close();
} }