The first is JSP pages and scripts.
This is a common function to check whether a user name exists.
Struts is used here.
<% @ Page contenttype = "text/html; charset = GBK" %>
<HTML>
<Head>
<Title>
Ajax
</Title>
</Head>
<Body bgcolor = "# ffffff">
<H1>
<Input name = "username" type = "text" maxlength = "20"/>
<Input id = "Chk-name-BTN" type = "button" value = "check account" onclick = "testname ('<% = request. getcontextpath () %> ') "/>
<Div id = "view_name"> </div>
</H1>
</Body>
</Html>
<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 the XMLHTTPRequest object
Function testname (PATH ){
// Path is used to obtain the system path
VaR view_name = Document. getelementbyid ("view_name ");
VaR Req = new XMLHttpRequest ();
If (req ){
Req. onreadystatechange = function (){
If (req. readystate = 4 & Req. Status = 200) {// determines the status. 4 is sent and 200 is complete.
If (req. responsetext = 0 ){
View_name.style.color = 'green ';
View_name.innerhtml = 'this user name can be used properly ';
} Else if (req. responsetext = 1 ){
View_name.style.color = 'red ';
View_name.innerhtml = 'this user name has been used ';
} Else {
View_name.style.color = 'red ';
View_name.innerhtml = 'the user name contains invalid 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 (""); // if the sending parameter is Req. Send ("username =" + user_name), use request to obtain
}
}
</SCRIPT>
The user name is not obtained on this JSP page. <Div> you can change the span parameter. For more information, see <div>.
The action that accepts the 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 outputs all characters. If the data volume is large, XML can be used for sending and receiving.
Return NULL;
}
}
Struts-config.xml
<Action type = "test. whw. Upload. ajaxaction" Validate = "false" Scope = "request" Path = "/ajax"/>
----------------------------
For Servlet
Web. 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 (){
}
}
-------------------------------------
For 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, and tomcat4.1.
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