Apart, directly to the code, believe that the need is the code rather than a pile of nonsense ...
1.java Code:
Copy Code code as follows:
Package TT;
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 Testa extends HttpServlet {
Private static final long serialversionuid = -7999241892841130740l;
protected void doget (HttpServletRequest request,
HttpServletResponse response) throws Servletexception, IOException {
Request.setcharacterencoding ("Utf-8");
String name = Request.getparameter ("name");
Response.setcontenttype ("Text/xml; Charset=utf-8 ");
Response.setheader ("Cache-control", "No-cache");
PrintWriter out = Response.getwriter ();
Out.println ("<pront>");
if (Name.equals ("Yangjinde")) {
Out.println ("<content>" + "Sorry, ' Yangjinde ' is already registered" + "</content>");
} else {
Out.println ("<content>" + "can register Oh" + "</content>");
}
Out.println ("</pront>");
Out.close ();
}
}
2.jsp Code:
Copy Code code as follows:
<%@ 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 ' index.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 are my page" >
<script>
Set a variable
var Xmlhttpreq=false;
Create a XMLHttpRequest Object
function Createxmlhttprequest () {
if (window. XMLHttpRequest) {//mozilla
Xmlhttpreq=new XMLHttpRequest ();
}
else if (window. ActiveXObject) {
try{
Xmlhttpreq=new ActiveXObject ("msxml2.xmlhttp");
}catch (e) {
try{
Xmlhttpreq=new ActiveXObject ("Microsoft.XMLHTTP");
}catch (e) {}
}
}
}
Send Request function
function Send (URL) {
Createxmlhttprequest ();
Xmlhttpreq.open ("Get", url,true);
Xmlhttpreq.onreadystatechange=proce; function that specifies the response
Xmlhttpreq.send (NULL); Send Request
}
function Proce () {
if (xmlhttpreq.readystate==4) {//object state
if (xmlhttpreq.status==200) {//information returned successfully, start processing information
var res=xmlhttpreq.responsexml.getelementsbytagname ("Content") [0].firstchild.data;
Window.alert (RES);
document.getElementById ("Data"). InnerHTML = res;
document.getElementById ("name"). Value = res;
}else{
Window.alert ("Sorry, the requested page has an exception");
}
}
}
Authentication
function Check () {
var Name=document.getelementbyid ("name"). Value;
if (name== "") {
Alert ("Please enter the content");
return false;
}
else{
Send (' login?name= ' +name);
}
}
</script>
</head>
<body>
<form action= "Login" method= "POST" >
<tr><td> Name: <input id= "name" type= "text" name= "name"/>
<input type= "button" value= "dot I try" onclick= "check ()"/>
</td>
</tr>
<tr><td><div id= "Data" > Wait, I'll change!! </div></td></tr>
</form>
</body>
</html>
3.xml configuration File Code:
Copy Code code as follows:
<?xml version= "1.0" encoding= "UTF-8"?>
<web-app version= "2.4 "
xmlns=" http://java.sun.com/xml/ns/j2ee "
xmlns:xsi=" Http://www.w3.org/2001/XMLSchema-instance "
xsi: schemalocation= "HTTP://JAVA.SUN.COM/XML/NS/J2EE
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
<servlet>
<servlet-name>login</servlet-name>
<servlet-class>tt. Testa</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login< ;/servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
< Welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
& Lt;/web-app>
