How do I deal with Warrior stuns?

Add in blocks, pulls, knock downs, knock backs, wards, condition cleanse and blinds as well, so thats a few ways to deal with stuns:

A hammer warrior will chain generally all of the 5 attacks, so if you dodge say Earthshaker, you might get hit with a Hammer Shock so they can line up Staggering Blow or Backbreaker. A good Hambow warrior will try to do all their Hammer attacks within their fire fields to maximise Might generation and to keep you stacked with burning.

The trick is to not let them chain, even stability isn't going to do much, you need to blind them during their AoE leap EarthShaker so they miss their Staggering blow, block them, make them come to your area damage (symbols, wells...). You need to be doing quick burst to keep your Vigor up immediately after you have interrupted them some how - so you can dodge more - you need to avoid 4 solid control effects.

Chill works well as a soft CC works as well. Save your condition damage to when their berserk stance has finished - sure their is an icon to indicate!

If you can nullify their CC and damage chain, without blowing your CC too much, dodge, blocks, soft CC once they switch to Bow, then its time to CC and burst them - not in their fire fields please. And constant cleansing please.

The hardest thing is most Hambow warriors will be high in vitality and have good toughness. I find I need at to at least survival 2 weapon swaps to get them down a bit and let them blow their cool downs, before applying several sequenced burst to counter them. In sPvP thats enough time for support to arrive to make it more fun.