According to this StackOverflow post... http://stackoverflow.com/questions/836647/migrating-from-netbeans-to-eclipse
...which linked me to this page as a solution... http://www.coderanch.com/t/458555/vc/Export-Netbeans-Eclipse
...apparently it's just a matter of creating a new project in Eclipse which points to the important files in the NetBeans project. The same solution is also present on the StackOverflow page with screenshots.
Another option that is mentioned is something to do with AntBuild, which I don't really know anything about, but I've noticed that Eclipse asks me if I want to Run using it when attempting to launch a class file outside of a project? (Sorry if that was long-winded.)
Not sure if JavaFX would go along with it, though.