More Servlets and JavaServer Pages™

9.8. Example: A Prohibited-Site Filter

Suppose you have a competitor that you want to ban from your site. For example, this competing company might have a service that accesses your site, removes advertisements and information that identify your organization, and displays them to their customers. Or, they might have links to your site that are in framed pages, thus making it appear that your page is part of their site. You’d like to prevent them from accessing certain pages at your site. However, every time their Web hosting company boots them off, they simply change domain names and register with another ISP. So, you want the ability to easily change the domain names that should be banned.

The solution is to make a filter that uses initialization ...