Intent

Introduce a common handler for all requests for a web site. This way we can encapsulate common functionality such as security, internationalization, routing and logging in a single place.

Class diagram

Applicability

Use the Front Controller pattern when

you want to encapsulate common request handling functionality in single place
you want to implements dynamic request handling i.e. change routing without modifying code
make web server configuration portable, you only need to register the handler web server specific way

Real world examples

Apache Struts

Credits