I did not read all your codes but it looks like you are trying to use a new AppUser object in your loginServiceAction class to check if user is logged in. This will not work since it is initialized to default values. You need to do:
Just a suggestion, don't use Struts 1. Its has already reached EOL.
If you have to for some reason use Filters and check if user is in session.
Do not give access to JSP directly, it should be from Action class.
When user logout invalidate session in action class.
Also if you don't want jsp pages cached then use this scriplet in JSP page: