How to setup the div border in my case?

How to setup the div border in my case?

I have a question regarding the div element border
I am trying to create bunch of divs that acts like a table
so
<div class='div'>first</div>
<div class='div'>second</div>
<div class='div'>third</div>
<div class='div'>four</div>
My css is
.div{
border: solid 1px black;
}
All my divs have borders but the problem is all my divs's top and bottom
border are 2 px instead of 1px because my css apply 1 px on every div. The
second and the third div have thinker border on top and bottom.
I can't really change the class name because it's dynamically generated.
Is there anyway to work around this issue?
Thanks a lot!