Not to my knowledge. You can manually drag the data dir elsewhere before doing the export, I suppose. Might become tedious if you do that frequently.
Why do you have a data folder if you don't want it exported? How do you plan to access the data there once exported? Perhaps just keep the folder out of the sketch dir.

when you run your sketch locally you can also access the data when it is in the root dir. but it wont be packed into the jar when exporting. so maybe thats a way to do it. although i dont understand why you should. your program wont work anymore if you need the data.

My data dir is over 200mb and because it contains textures, it won't map into the jar.  So I'm moving it in and out of the data directory before every export, then I put it back into the app path.  Would be a lot easier if I could just tell it to exclude the data dir during export.

If you're loading images, you do have the option to use the full path to the file on your machine (or alternatively a URL, if the image is online...).  e.g.:

1. loadImage("C:/Documents and Settings/ben/My Documents/My Pictures/image.jpg");

Then you don't need to duplicate your images in every version of your sketch... and IIUC they shouldn't get packaged into the jar.

yes, thats a good idea, if you have a large amount of data. and like i suggested it doesnt get packed as well as only the content of the data folder get packed.

what i often do when i have a large data file i dont want to diplicate with every version of my sketch i just create a data folder in the root folder and then link to it when loading like this :

1. loadImage(".../data/image.jpg");