如何从file2替换相同数量的file1

i have a list of query and hits gi in one file (file1) . i have another file in which complete name of hits is there(file2), now i want to replace Hits gi from file1 to file2 that have the complete Hit name. i want that gi must be replace with the same gi in front of it's each corresponding Query.i have a list of query and hits gi in one file