You'll need to do a file upload of the Excel data.
Once you have that data on your server, there are several
Java libraries that can extract data from it into forms more friendly to general Java use.
There's really nothing JSF-specific in this, excepting the (optional) use of a JSF page with a JSF file upload control on it.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.