Get username via servlet from Tomcat session

Question

I have a servlet that uploads files. In order to distinguish files, I want to put the username,date, and time in the new filename (I already have the date and time). Can somebody point me to an example that will get the username from the tomcat session?
thanks in advance,
Chuk

Answer 1

Assuming that the user has logged in to your web application through something like form-based authentication you can use:
request.getUserPrincipal()to get hold of information about the user.
However, if they've not logged in with your site then you'll get nothing back. Also, depending on the version of Tomcat you've got you may encounter some stupid behaviour (getting null back) if the Servlet isn't a protected resource.
Failing that you can try getRemoteUser to try to obtain some information about the authenticated user; I've had some problems with this in the past with IIS and haven't tried it with Tomcat.
If you want more information about how to get your user to authenticate against your web application realm then just ask...
Hope this helps.