Filling in request values with groovy

Can someone provide a code snippet that will read data from a file (key=value) and insert values into a request node i.e, "Login" and run the request X number of times?

for example:
dataFile.txt
username=Login0
password=Soap0
username=Login1
password=Soap1
username=Login2
password=Soap2
username=Login3
password=Soap3
...

request:

 

 
     
        ?
        ?
     
 


then, loop through request with values in file:
Iteration 1:

 

 
     
        Login0
        Soap0
     
 


Iteration 2:

 

 
     
        Login1
        Soap1
     
 


etc...

Thanks!