Just store your data in one file for each map, simple solution. Each row is a row in the map, and each value between commas in a column:
1,5,6,3,5
4,8,9,6,4
2,4,6,7,6
0,0,1,3,2
5,7,4,2,1
That could be a 5 x 5 map. Then just read the file and split data into a 2D array or a list, depending on your programming language.