I don’t quite follow what you are asking… if you want to see the page that Tomcat generates, that just requires using a browser (the little “World” icon in your toolbar) to point it at your JSP page (e.g. http://localhost:8080/myapp/mypage.jsp)
If you wanted, for example, another tab in the editor to show you exactly what the running result is, there is not support for this at this time, but it’s a good idea for a future enhancement. (Unfortunately, special frameworks can make this hard to do well, for example, custom extension mappings).