how to set restrict access to servlet?

[Xiaofeng Chen]

Hi, all: I have some servlets running in tomcat. I would like to set
restrict access
to these servlets so that the servlets can get the username through
request.getRemoteUser().
Do I do any configuration in server.xml or web.xml? Do I need a .htaccess
file in the servlet
and jsp directory? Thanks for any help!