最近比较闲，就把以前用过的技术串一下做个手札，方便以后自己偷懒，小鸟你们幸福了。
首先主要是将javascript版本ajax做下注释：ajax异步刷新主要是将所需条件拼成字符串传入后台，处理之后，直接调用回调函数将所得数据返还给页面，并加以显示，因为还在本页面，所以不用刷新页面，懂了了吧，本篇也用encodeURI对字符串做了加密，并在类里做了解码，其中需要一些注意的地方在源码里做了注释。get/post两种提交方式，但get提交容易乱码，一定多加注意
jsp页面：
<%@ 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%>">
<script type="text/javascript" >
var xmlHttp;
function createxmlHttpRequest(){
if(window.XMLHttpRequest){
xmlHttp= new XMLHttpRequest();//IE7+,FireFox,Opera,Safari,Chrome
}else{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
}
function test(){//get
//获取参数
//var unames=encodeURI(document.getElementById("username").value);//一次编码java用new String(name.getBytes("ISO8859-1"), "UTF-8"）解码
var unames=encodeURI(encodeURI(document.getElementById("username").value));//两次编码才能用java.net.URLDecoder.decode(name,"utf-8");解码
var pws=encodeURI(document.getElementById("password").value);
createxmlHttpRequest();
xmlHttp.onreadystatechange=readyState;
//function(){
//alert(xmlHttp.readyState+"=="+xmlHttp.status);//判断请求状态
//}
xmlHttp.open("get","AjaxServlet1?msg=gets&name="+unames+"&pwd="+pws+"&timeStamp="+new Date().getTime(),true); //get 方式提交中文会出现乱码，encodeURI()/encodeURIComponent()将中文转成16进制编码，把字符串作为URI进行编码
xmlHttp.send(null);
}
function testp(){//post
//获取参数
var unames=document.getElementById("username").value;
var pws=document.getElementById("password").value;
createxmlHttpRequest();
xmlHttp.onreadystatechange=readyState;
xmlHttp.open("post","AjaxServlet1",true);
xmlHttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
var str="msg=posts&name="+unames+"&pwd="+pws+"&timeStamp="+new Date().getTime();
xmlHttp.send(str);//send 可用于传参
}
function readyState(){
if(xmlHttp.readyState==4){
if(xmlHttp.status==200){
var msg= xmlHttp.responseText;
//alert(msg);
document.getElementById("result").innerHTML=msg;
}
}
}
</script>
<title>js异步刷新</title>
</head>
<body>
<center>
<div id="response">
</div>
用户：<input type="text" name="uname" id="username"><br>
密码：<input type="text" name="pw" id="password"><br>
<input type="button" name="button" value="get确定" onclick="test();"/>
<input type="button" name="button" value="post确定" onclick="testp();">
<div id="result">
</div>
</center>
</body>
</html>
这里是servlet/action Java代码:
package com.cstp.javascript;
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;
@SuppressWarnings("serial")
public class AjaxServlet1 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 {
//设置编码，防止乱码
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
//接收参数
String msg=request.getParameter("msg");
if(msg.equals("gets")){
// String name=new String(request.getParameter("name").getBytes("ISO8859-1"), "UTF-8"); //一次编码，java里进行解码操作
String name=java.net.URLDecoder.decode(request.getParameter("name"),"utf-8"); //decode解码页面必须两次编码，java里进行解码操作
String pwd=request.getParameter("pwd");
System.out.println(name+","+pwd);
PrintWriter out = response.getWriter();
out.println("ajax响应get，结果返回"+name+","+pwd);
}else if(msg.equals("posts")){
String name=new String(request.getParameter("name").getBytes("utf-8"), "UTF-8"); //一次编码，java里进行解码操作
String pwd=request.getParameter("pwd");
System.out.println(name+","+pwd);
PrintWriter out = response.getWriter();
out.println("ajax响应post，结果返回"+name+","+pwd);
}
}
}
上面是javascript版ajax，下面将喜欢jquery版的也分享给JQ友们：
页面上：
<script type="text/javascript">
//方式①
function circum(lon,lat){
$.ajax({
url: "JQAjaxServlet?method=jsons",
contentType: "application/x-www-form-urlencoded; charset=utf-8",
type : 'post',
dataType:"json",
async: false,
data : { //传参给后台
'lon' : lon,
'lat' : lat
},
success: function (data) { // 接后台返回result
在这里data为后台返回数据，你可以尽情处理了
}
});
}
</script>
后台：servlet/action里
类里对数据处理的方法同上，就不再累赘了