I'm making this because many people can't seem to fight hammer-users and call it spam. For your info, spurs move you almost as much as hammers, so don't think that's helping them. :P
Please, ask anything about how to fight hammers or tips for those having issues. DO NOT HATE ON HAMMERS, BECAUSE THAT DOESN'T BELONG HERE.
My first tidbits is this: after they use their first swing, run towards the hammer user. You'll find that they'll dash right past you! If you use guns or bombs, dropping a bomb right as they dash or shooting them can possibly lead to good results.
I don't have much tips. But one time, a hammer spammer spammed his hammer at me, and accused me for spamming just for making one gran faust swing and missed. He started to accuse me and made lies that I stole a bound Gran faust. He did this to other people >_>