Ajax|js First is the JSP page and the script, in order to conveniently write in one inside
This is a very common feature that detects whether a user name exists
This is with struts.
<%@ page contenttype= "text/html; CHARSET=GBK "%>
<title>
Ajax
</title>
<body bgcolor= "#ffffff" >
<input name= "username" type= "text" maxlength= "/>"
<input id= "chk-name-btn" type= "button" value= "Detect account"/>
<div id= "View_name" ></div>
</body>
<script language= "JavaScript" >
if (window. ActiveXObject &&!window. XMLHttpRequest) {
Window. Xmlhttprequest=function () {
return new ActiveXObject (Navigator.userAgent.toLowerCase (). IndexOf (' msie 5 ')!=-1)? ' Microsoft.XMLHTTP ': ' msxml2.xmlhttp ');
};
}//get XMLHttpRequest Object
function TestName (path) {
Path is to get system paths
var View_name=document.getelementbyid ("View_name");
var req=new xmlhttprequest ();
if (req) {
Req.onreadystatechange=function () {
if (req.readystate==4 && req.status==200) {//Judgment status, 4 is sent, 200 completed
if (req.responsetext==0) {
View_name.style.color= ' green ';
View_name.innerhtml= ' The user name can be used normally ';
}else if (req.responsetext==1) {
View_name.style.color= ' Red ';
View_name.innerhtml= ' The user name has already been used ';
}else{
View_name.style.color= ' Red ';
View_name.innerhtml= ' The username contains illegal characters! ’;
}
}
}
Req.open (' POST ', path+ '/ajax.do ');//struts
Req.open (' POST ', path+ '/ajax.servlet ');//servlet
Req.open (' POST ', path+ '/ajax.action ');//webwork
Req.setrequestheader (' Content-type ', ' application/x-www-form-urlencoded ');
Req.send ("")//Send parameter If there is a parameter req.send ("Username=" +user_name);
}
}
</script>
This JSP page does not get user name, is demo. There are <div> can change span, specific role to ask Art bar.
An action that accepts an AJAX request.
Import org.apache.struts.action.*;
Import javax.servlet.http.*;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
Import Java.io.PrintWriter;
/**
* <p>title:ajaxaction </p>
*/
public class Ajaxaction extends Action {
Public Actionforward Execute (actionmapping mapping,
Actionform form,
HttpServletRequest request,
HttpServletResponse response)
Throws Exception {
PrintWriter out = Response.getwriter ();
Out.print (1);//ajax get all the output of the character. If the volume of data is large, you can also use XML to send and accept
return null;
}
}
Struts-config.xml
<action type= "Test.whw.upload.AjaxAction" validate= "false" scope= "request" path= "/ajax"/>
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If this is a servlet
Xml
<servlet>
<servlet-name>ajaxservlet </servlet-name>
<servlet-class>servlet. Ajaxservlet </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ajaxservlet </servlet-name>
<url-pattern>/ajaxservlet .servlet</url-pattern>
</servlet-mapping>
Ajaxservlet.java
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;
public class Ajaxservlet extends HttpServlet {
Logger log = Logger.getlogger (This.getclass ());
public void doget (HttpServletRequest request, httpservletresponse response)
Throws Servletexception,ioexception {
Response.setcontenttype ("Text/xml; CHARSET=GBK ");
PrintWriter out = Response.getwriter ();
Out.print (2);
}
}
Process the HTTP Post request
public void DoPost (HttpServletRequest request, httpservletresponse response)
Throws Servletexception, IOException {
Doget (request, response);
}
Process the HTTP put request
public void DoPut (HttpServletRequest request, httpservletresponse response)
Throws Servletexception, IOException {
}
Process the HTTP Delete request
public void Dodelete (HttpServletRequest request,
HttpServletResponse response) throws Servletexception, IOException {
}
Clean up resources
public void Destroy () {
}
}
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If it's webwork,
Xwork.xml
<action name= "Ajax" class= "Com.whw.upload.action.webwork.AjaxAction" method= "Ajax"/>
Ajaxaction.java
Import Java.io.PrintWriter;
public class Ajexalbumaction extends Actionsupport implements action{
public void Ajax () throws IOException {
PrintWriter pw = Servletactioncontext.getresponse (). Getwriter ();
Servletactioncontext.getresponse (). setContentType ("TEXT/HTML;CHARSET=GBK");
Pw.print (1);
Pw.close ();
}
}
This example can be run in winXPsp2, JB9, eclipse3,j2sdk1.4.1, TOMCAT5, Tomcat4.1
