Thread: mantaining sessions in WebApp

hi to all
as I'm creating a Web App. using struts and servlets. My App. is almost complete excluding one thing i.e. sessions. Here by sessions i mean that as when ever we login to any websites say email account and we know that our inbox can only be accessed "if we login !", this is what i'm thinking to implement.
About Application:
1.this is a small project, i have to create a site which will be used for viewing the movies running in theatres and can also see the upcommings of next seven days. this i implemented with little help of database, just to read the current system date and then show results on web page for the next seven days.
2. next service provided for the users, after registering with the site they can even book tickets. here is where sessions are must as persons who are "not registered must not able to see booking page even if specified url is provided" as app contains a page which collects the user data inorder to book tickets and the url is ( in my application )

"/rainbowentertainment/booking.view"

.
here is what a problem arises as if i enters this url in the browser then the booking page is displayed!
I don't know how to prevent this?
any suggestions regarding this is most welcomed
thank you