How do I exclude a specific URL in a filter in Spring?

Question

I have a basic application filter config that looks like this:

@Configuration
public class ApplicationFilterConfig {

    /**
    * Check if user is logged in
    */
    @Bean
    public FilterRegistrationBean applicationFilterRegistration() {

        // created a collections that need logins to be validated.
        ArrayList<String> urlPatterns = new ArrayList<String>();
        urlPatterns.add("/home");
        urlPatterns.add("/about");
        urlPatterns.add("/contact");
        // ... 

        LoginFilter loginFilter = new LoginFilter();
        FilterRegistrationBean registration = new FilterRegistrationBean(); 
        registration.setFilter(loginFilter);
        registration.setUrlPatterns(urlPatterns);
        registration.setOrder(1);
        return registration;

    } 


}

However, the list urlPatterns grows to be very long, even when using the star annotation (e.g. /employees/*). The main reason why I don't just use /* is because I don't want to require login validation for my login page. If I did, it'd create an infinite loop of redirects.

Does the FilterRegistrationBean class allow you to apply a filter to all URL patterns except certain patterns?

I could put everything except the login page in a directory and set my URL pattern to be /subdirectory/* but that adds an unnecessary level of depth to every file in my webapp.

Answer 1

FilterRegistrationBean doesnot provide(atleast until now) any method to exclude URL patterns. But it can be taken care from from Filter implementation(in this case its LoginFilter). Implement LoginFilter by extending OncePerRequestFilter which has a method called shouldNotFilter() which can be overriden to suit your needs.

    public class LoginFilter extends OncePerRequestFilter {

        private List<String> excludeUrlPatterns = new ArrayList<String();

        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
                FilterChain filterChain) throws ServletException, IOException
        {
            // Implementation....
        }

       @Override
       protected boolean shouldNotFilter(HttpServletRequest request) throws ServletException 
       {
           // Populate excludeUrlPatterns on which one to exclude here
       }

    }

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