Mini Schnauzer Barking Issue!

Question
Hello
We have a 2 year old male mini schnauzer.  He is a bright, loving member of our young active family.  The only issue with Max is he has a major barking issue in certain situations.  The biggest issue is when we have a guest or visitor to the house.  I expect him to bark when someone comes to the door - but the issue is he DOES NOT STOP.  I am at the point where I dread having any visitors and we can't live that way.  We previously owned a mini schnauzer who would bark when the bell rang or someone came to the door but as soon as he realized that we welcomed the visitor - he would relax and chill out.  Max will follow a guest around the house and bark at them wherever they go.  We try to quiet him and give treats when quiet, we try to keep him on a leash in the house when a visitor arrives - but nothing works!!
He will also bark incessantly when outside on a walk and sees a person.  We live in a neighborhood and we see lots of people so it makes our walks very stressful when he will not stop barking.  
I think he is well socialized as he does go to doggie daycare 1 - 2 days a week to get to play with other dogs.  He loves to play with other dogs and the daycare folks tell me that he is the leader of the pack and is the one who gets the whole group going and is very excitable.
I don't know what to do!  We are having a new baby soon which will inevitably bring lots of guests to our house and I just can't handle his behavior anymore.  
I welcome any suggestions you may have.  I had a local trainer tell us to get a barking collar which I feel is mean - do you think that is necessary?  Please don't get me wrong - I expect our dog to bark since he is a dog.  I just need to find a way to let him know its ok to stop.
Thank you so much!!!
Danielle

Answer
You need to get this dog into on-going obedience classes for several months and work with him every day. You also need to start practicing "Nothing in Life is Free" with him; he must work for every single thing he wants in life.
http://k9deb.com/nilif.htm

Most schnauzers hate water, so put water in a spray bottle and set it to shoot a stream of water. Whenever he starts to bark, tell him to "BE QUIET!" and shoot him in the face with the water. If he doesn't mind water, put Bitter Apple in the bottle diluted about 75% BA/25% water. Be sure you do not get this one in his eyes (aim for his mouth... or his general area)! Carry the bottle with you at all times, particularly in the beginning, and correct him every single time he barks. Praise when he is quiet.