/u/PlatypusKeeper and I discussed Thor symbolism, particularly hammers, and the lack of homogeneity in Scandinavian and Germanic belief systems in this thread a little while ago.

As a weapon for battle, hammers are unlikely to have been anybody's first choice. Sources like The Battle of Brunanburh, The Battle of Maldon and Asser's Vita Ælfredi tell us that, broadly speaking, 9th and 10th century Danish warfare was similar to English contemporaries in the extent to which it was based around a shield wall armed with spears, supported by skirmishers. Anybody wealthy or powerful enough to not fight with a spear of some description is more likely to have carried a sword, or potentially an axe.