Eclipse has built-in support for Xinput controllers, however it does not support DirectInput. It simply wouldn't work well if I tried to integrate it into Eclipse itself (based on how GameMaker handles it) but there is still a way to use that controller with a program called Joy2Key.
It's a fairly simple program to use. Open it up and click on "Auto Setting Wizard" and then press the key you want to map to. Eclipse will have to be set to the keyboard setting for it to work. Once you're all done just minimize the program and you're good to go!
I do intend on trying to add DirectInput support in the future, but I won't keep it unless it works flawlessly. I'm doing some brainstorming to see what methods I could try. In the meantime, Joy2Key works great.