How can i stop my dog from barking?

My dog barks constantly when he is not around us. When he goes outside he does his business and then runs to the door and barks like crazy till we let him in. When we let him in and he is wet we have a half door to keep him from roaming upstairs and getting everything wet and he has the basement to go in and he still barks. We have tried putting him my room where he sleeps everyday and he is a little more calm but still barks. We have tried a spray bottle doesn't work. Shock collar doesn't work ignoring him and hoping he would get used to it and it doesn't work. We have tried letting him in when he takes a short break from barking and telling him he is a good boy and we have tried treats as well. My parents are about done and wanting to get rid of him if i cant find a way to get him to stop barking all the time. Is there anything else i can do to try to stop him from barking all the time i love him and don't want him to have to go to a new home. Please let me know if there is anything else i could try that would stop him.