There are a lot of different kind of collars that you can buy for this problem. My neighbor got the shock collar.(it doesn't really hurt it more scares them) It worked really well. And after getting zapped a few times she didn't even have to turn it on.All she had to do was leave it on the dog.
There also is the citrus collar. Everytime your dog barks it sprays citrus and usally the dog doesn't like the smell so they stop barking.
Hope this helps