首先，我们仍然是对Struts应用来做配置，仍然是在struts-config,xml文件里做配置，如下：
<action type="com.ajax.CheckAction"
scope="request" path="/ajax/check">
<forward name="success" path="/check.jsp"/>
</action>
跟普通的Struts应用的配置一样，只是没有ActionForm的配置。下面是Action类：
package com.ajax;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.DynaActionForm;
/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class CheckAction extends Action
{
public final ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
throws Exception
{
System.out.println("haha...............................");
String username= request.getParameter("username");
System.out.println(username);
String retn;
if("educhina".equals(username)) retn = "Can't use the same name with the old use,pls select a difference...";
else retn = "congraducation!you can use this name....";
PrintWriter out=response.getWriter();
out.write(retn);
out.close();
return mapping.findForward("success");
}
public static void main(String[] args)
{
}
}
我们可以看到里面的逻辑跟上例中Servlet里的逻辑一样。最后，我们来看看JSP:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Check.html</title>
<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">-->
</head>
<script type="text/javascript">
var http_request = false;
function send_request(url) {//初始化、指定处理函数、发送请求的函数
http_request = false;
file://开始初始化XMLHttpRequest对象
if(window.XMLHttpRequest) { file://Mozilla 浏览器
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {//设置MiME类别
http_request.overrideMimeType('text/xml');
}
}
else if (window.ActiveXObject) { // IE浏览器
try {
http_request = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
http_request = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!http_request) { // 异常，创建对象实例失败
window.alert("不能创建XMLHttpRequest对象实例.");
return false;
}
http_request.onreadystatechange = processRequest;
// 确定发送请求的方式和URL以及是否同步执行下段代码
http_request.open("GET", url, true);
http_request.send(null);
}
// 处理返回信息的函数
function processRequest() {
if (http_request.readyState == 4) { // 判断对象状态
if (http_request.status == 200) { // 信息已经成功返回，开始处理信息
alert(http_request.responseText);
} else { file://页面不正常
alert("您所请求的页面有异常。");
}
}
}
function userCheck() {
var f = document.forms[0];
var username = f.username.value;
if(username=="") {
window.alert("The user name can not be null!");
f.username.focus();
return false;
}
else {
send_request('ajax/check.do?username='+username);
}
}
</script>
<body>
<form name="form1" action="" method="post">
User Name:<input type="text" name="username" value="">
<input type="button" name="check" value="check" onClick="userCheck()">
<input type="submit" name="submit" value="/oblog312/submit">
</form>
</body>
</html>
我们可以看到，JSP基本是一样的，除了要发送的url：ajax/check.do?username="+username。