In my server, I installed the apache and tomcat. But, when I access the my site, www.mysite.com, will for the apache. I want that access the tomcat, because I will put my site in tomcat. How to ?
Set up a connector from Apache to Tomcat (one such connector is mod_jk). Here are some docs on how to do it:
There's also this ServerFault question from a while ago:
(Actually, look at the Related topics columns on the right of this page; you'll see a bunch of things related to Apache and Tomcat)
Basically, Apache is in front of Tomcat, and will act as a reverse proxy. Apache can be used to handle the static content of your site, and Tomcat the dynamic part.
You can do it enabling the ProxyPass directive in apache config file.