How can I include a .jsp
file into a facelet?
This is by default not supported. You need to create a custom component for this. You can find complete examples in this blog and this answer. The OmniFaces component library has a reuseable <o:resourceInclude>
component for this.
<html ... xmlns:o="http://omnifaces.org/ui">
...
<o:resourceInclude path="/foo.jsp" />