This is an easy way to play if it kills me, I've never written tab before so be patient,  
I know this isn't how Mraz plays it but it is the easiest way enjoy, 

feel free to leave comments 


e---2---------------3-| 
b---3-----------------| 
G---2------1----------| 
D---------------------| 
A------------------2--| 
E------------------3--| 


chorus 

e---2-------2-----2-----3 the 222--| thing is laying first finger across strings at 2nd fret 
b---3-------2-----2/3--------------| 
G---2------2-----2-----------------| 
D------------------4---------------| 
A----------4-------------2---------| 
E-------------------------3--------| 

the run that leads out of the chorus is 


A---0/ 1 so open A then fret A string 1st fret 
E---3 

then 

e--- 
b---1 
G--- 
D---2 
A---3 
E--- 


then the whole thing repeats 

the 2/3 thing= still laying finger across the three strings at 2nd fret but also with  
finger fretting b string 3rd fret