Servlet Filter - Dont apply filter to a specific one

Question

I have a web-application with login screen backed up by an Authentication Filter.

I have the following in my web.xml

<filter>
    <filter-name>AuthenticationFilter</filter-name>
    <display-name>AuthenticationFilter</display-name>
    <filter-class>com.mycompany.secutity.AuthenticationFilter</filter-class>
</filter>

And I have the following mapping -

<filter-mapping>
    <filter-name>AuthenticationFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

But now I want to add an exception where for a specific servlet /web/MyNewServlet, I want to bypass the authenctication filter. How can we do this?

Answer 1

There are two ways in which you could do this:

• Remap the /* pattern to another pattern like /subdir/*, and thereby avoid the AuthenticationFilter from being applied against /web/MyNewServlet. This is a cumbersome process as you might have several URLs in your web-application that now need to be remapped. I would suggest doing this early in your development, or when you do not have too many URLs to remap.
• Include an exclusion rule programatically inside your Filter implementation. You will need to use HttpServletRequest.getServletPath and similar methods to verify if the URL fragment contains /web/MyNewServlet, and then chain the filter to the next filter or the servlet, instead of executing the body of the filter.