They do have hangers in the closets. However there are probably not going to be enough of them. Probably about 10 or so. We always bring a garment bag as one of our pieces of luggage so we have extra hangers.
We also use a garment bag, so lots of stuff is already on hangers. Once or twice I've just doubled up on some hangers or ask your cabin attendant for some extras, he/she will be happy to get them for you.