Hi patricktwo:
You can call GUI components in web if you have an Applet, and since an applet runs in the client machine, a file chooser will list files on the client filesystem (anyway you can't access those files, if your applet is not signed).
You must create your own Chooser, which must receive a list of the files from the server, so it will show them and you can check which one has been selected by the user. Extend from JDialog.
Hope it helps.
Pedro Andrés Solorzano
Pontificia Universidad Javeriana
Bogotá, Colombia, SurAmérica.