I googled a bit and found that it can be done by services--->servers--->add new, but when I try to add new Tomcat server this way, it doesn\'t appear in the list.
If TomCat is install. Perhaps it is not installed Java EE. Services-> plug-ins-> additional plug-ins-> in the search dial tomcat. and install the module java ee. then in the services, servers, add the tomcat server.
In Netbeans 8 you may have to install the Tomcat plugin manually. After you download and extract Tomcat follow these steps:
While installing Netbeans itself, you will get an option which servers needs to be installed and integrated with Netbeans. First screen itself will show.
Another option is to reinstall Netbeans by closing all the open projects.
I had same issue. No need to re install.
In Netbeans 6.0 , Find RunTime -> Servers - > Add server -> select Tomcat install 'root' directory
In Netbeans 7.x -> Tools -> Servers-> Add server -> select Tomcat install 'root' directory
Here is in Netbeans Wiki.
http://wiki.netbeans.org/AddExternalTomcat