If it's a simple file, just place in public webcontent (there where you put your static and JSF files) and create a link.
<h:outputLink value="/files/file.ext">link</h:outputLink>
The servletcontainer will worry about applying the correct headers.
If it's located outside the public webcontent for some specific reasons (e.g. in a fixed path at server machine, or in a database), then create a servlet which gets an InputStream
of it and writes it to the OutputStream
of the response along at least the Content-Type
, Content-Disposition
and Content-Length
headers. You can find here a simple kickoff example. Also that can simply be linked on the servlet's url-pattern
.
If it's to be dynamically generated and depending on the JSF specific request parameters, then you can also do so in a managed bean action which is bound by h:commandLink
or h:commandButton
, but you only need to ensure that you call FacesContext#responseComplete()
at end of bean's action method to prevent JSF from taking the navigation in hands. The same kind of servlet code can be reused to stream the file. You can find a kickoff example in this answer.