Barrier Mechnaics

Right now I'm just curious, but let say we have 2 of the same champions(champ1 and champ2 for future reference), both have full hp and have Barrier as a summoner spell. Now champ1 attacks champ2 who used his Barrier right before champ1 attacked. champ1's dmg is more than the amount of shielding champ2 gets from Barrier. Is the excess dmg ignored or is the excess dmg still given to champ2's hp? Is this the same for all shields.

I know this is a pretty weird/stupid question to ask because for balancing reasons, the answer should be obvious, but I want to make sure and I can't exactly test this.