Is doFilter() executed before or after the Servlet's work is done?

Question

The javax.servlet.Filter object can be used both for authentication (where the Filter needs to catch the request before any servlet work needs to be done) and for XSLT trans

Answer 1

According to the servlet2.3 specification filter is performed according to web.xml configuration of filter- mapping sequence Ref-http://www.programering.com/a/MTMyADOwATI.html

Answer 2

The filter chain in essence wraps the servlet invocation. The chain will process all links until it hits the "bottom", then allow the servlet to run, and then return up the chain in reverse. For example, if you have a new "example filter", your doFilter() method may look like this:

public void doFilter(ServletRequest request,
      ServletResponse response, FilterChain chain) 
      throws IOException, ServletException {
// do pre-servlet work here
chain.doFilter(request, response);
// do post servlet work here

}