How to check if a user is logged in when using auth-method FORM

Question

I am using auth-method FORM with apache tomcat to authenticate users. I am using the default j_security_check action.

If a user has signed in, I must display a Sign out link. Else a sign in link. How do I check if the user has signed in?

Also, how do I log a user out?

Answer 1

You can use HttpServletRequest.getUserPrincipal() and check it to find the logged in user.

Answer 2

The state of being logged in is identical to the condition that HttpServletRequest.getUserPrincipal() returns non-null.