Filter of a small anti-leech Image

The filter of a small anti-leech image can be used together

 

Public class imageredirectfilter implements filter {

Public void Init (filterconfig config) throws servletexception {
}

Public void dofilter (servletrequest req, servletresponse res,
Filterchain chain) throws ioexception, servletexception {

Httpservletrequest request = (httpservletrequest) req;
Httpservletresponse response = (httpservletresponse) RES;

// Disable caching
Response. setheader ("cache-control", "No-store ");
Response. setheader ("pragrma", "No-Cache ");
Response. setdateheader ("expires", 0 );

// Link Source Address
String Referer = request. getheader ("Referer ");
System. Out. println ("refer is" + Referer );

If (Referer = NULL |! Referer. Contains (request. getservername ())){

/**
* If the link address is from another website, an error image is returned.
*/
Request. getrequestdispatcher ("/error.gif"). Forward (request,
Response );

} Else {

/**
* The image is displayed normally.
*/
Chain. dofilter (request, response );
}

}

Public void destroy (){
}
}

 

 

Web. xml:

<Filter-mapping>
<Filter-Name> imageredirectfilter </filter-Name>
<URL-pattern>/upload/images/* </url-pattern>
</Filter-mapping>