It is not possible to save the file directly from Resty.
https://github.com/resty-gwt/resty-gwt/issues/341
The most common workarounds to download files using AJAX are not using AJAX at all.
- You can simply change the URL (using window.location) or (using javascript) create or;
- create a form (using JS) and post that form.
In my projects, I simple create a URL to my REST endpoint attaching any query parameters needed and use it as the href to a link.
For instance, if your RestyGwt endpoint points to /entity/1/bytes
just do
new Anchor("Download", "/entity/1/bytes");
your endpoint must produce a downloadable file type say:
@Produces("text/txt")