java - Make servlet filter for all 404 responses -

i want make custom filter extends javax.filter, when 404 status of response return static html page. not work , wondering why. here filter:

@webfilter("/*") public class pagenotfoundfilter implements filter {      @override     public void dofilter(final servletrequest request, final servletresponse response, final filterchain filterchain)             throws ioexception, servletexception {         httpservletresponse httpresponse = (httpservletresponse) response;         if (httpresponse.getstatus() == 404) {             httpresponse.sendredirect("pages/pagenotfound.html");         }         filterchain.dofilter(request, response);      } 

but nothing happens, why?

note: not want use:

<error-page>   <error-code>404</error-code>   <location>/pages/pagenotfound.html</location> </error-page> 

but filter

you test status code before request processed (and before 404 error set).

so need test status code after have called filterchain.dofilter(request, response);

but not work either because when response.senderror(404) called response committed , can't redirect.

therefore best use <error-page> mechanism.