问题
Currently in my app when a user types some illegal destination in the URL bar, sees this:

I would like to make it more beautiful and customize it with my own markup and a bit of css.
-Do i need to program that on my app or i have to configure that in the application server?
-Where should i start from if i want to do that?
回答1:
You can declare custom <error-page>
s in web.xml
depending on <error-code>
(the HTTP status code) or <exception-type>
(the full qualified exception class name which was been thrown, e.g. javax.faces.application.ViewExpiredException).
<error-page>
<error-code>404</error-code>
<location>/WEB-INF/errorpages/404.xhtml</location>
</error-page>
You've all freedom to fill in the markup in 404.xhtml
.
来源:https://stackoverflow.com/questions/7294171/how-to-create-custom-404-messages-in-jsf-2-0