用到Jquery插件：http://imakewebthings.com/jquery-waypoints/
示例：
<%@ 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>lazyload</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Infinite Scrolling with jQuery Waypoints</title>
<meta name="description" content="An example of how to build an infinite scrolling page on top of the jQuery Waypoints plugin">
<meta name="viewport" content="width=480">
<script src="jslib//modernizr.custom.js"></script>
</head>
<body>
<div id="wrapper">
<center>
<table id="container" style="border:1px solid #96C2F1; background-color: #EFF7FF; width: 300px; height: 100px; margin: 0px auto;">
<tr>
<td>id</td><td>name</td>
</tr>
<tr>
<td>2</td><td>Lucy</td>
</tr>
<tr>
<td>3</td><td>James</td>
</tr>
<tr>
<td>4</td><td>Gaga</td>
</tr>
</table>
</center>
<div id="footer">
</div>
</div>
<script src="jslib/jquery-1.7.1.js"></script>
<script src="jslib/waypoints.js"></script>
<script type="text/javascript"><!--
$(document).ready(function() {
var $loading = $("<div class='loading'><p>Loading more items…</p></div>"),
$footer = $('#footer'),
opts = {
offset: '100%'
};
$footer.waypoint(function(event, direction) {
$footer.waypoint('remove');
$('body').append($loading);
//alert($('#container tr:last td:first').text());
var id=$('#container tr:last td:first').text();
$.post('lazyload', {id: id}, function(data) {
if(data!=-1){
//alert("call back:"+data);
var jsons = eval(data);
//alert(jsons);
for(i in jsons){
$('#container').append("<tr><td>"+jsons[i].id+"</td><td>"+jsons[i].name+"</td></tr>");
}
//$('#container').append($data.find('.article'));
//$('#container').append($data);
$loading.detach();
//$('.more').replaceWith($data.find('.more'));
$footer.waypoint(opts);
}else{
//alert('nodata');
$loading.detach();
}
});
}, opts);
});
--></script>
</body>
</html>处理ajax请求的servlet
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.hp.bean.User;
public class LazyLoadAction extends HttpServlet {
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
int id=Integer.valueOf(request.getParameter("id"));
System.out.println("-----------id:"+id);
List<User> list = getUserList(id, id + 30);
if(list.size()>0){
StringBuilder sb=new StringBuilder();
sb.append("[");
for(int i=0; i<list.size(); i++){
User u=list.get(i);
sb.append("{name:'" + u.getName() + "',id:" + u.getId() + "},");
if(i==list.size()-1)
sb.append("{name:'" + u.getName() + "',id:" + u.getId() + "}]");
}
System.out.println(sb.toString());
out.print(sb);
}else{
out.print("-1");
}
out.flush();
out.close();
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
public static List<User> getUserList(int start,int end){
String url="jdbc:mysql://localhost:3306/test";
String jdbcdriver="com.mysql.jdbc.Driver";
Connection con=null;
List<User> list=new ArrayList<User>();
try {
Class.forName(jdbcdriver);
con=DriverManager.getConnection(url, "root", "root");
String sql="select * from user where id>? and id<?";
PreparedStatement pst=con.prepareStatement(sql);
pst.setInt(1, start);
pst.setInt(2, end);
ResultSet rs=pst.executeQuery();
while(rs.next()){
User user=new User();
user.setId(rs.getInt(1));
user.setName(rs.getString(2));
list.add(user);
}
rs.close();
con.close();
}catch(Exception e){
e.printStackTrace();
}
return list;
}
}
public class User {
private Integer id;
private String name;
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;
}
}