First, off, never fear.

However, I was warned by a very experienced professional to bring a knife, so bring a knife I will... I think I'll pass on a spear, though.
I can imagine situations where a big, strong knife might be necessary; approaching a downed porker which may or may not be deceased, and approaching a live pig held at bay by dogs. In either case, it might be difficult or impossible safely to fire a rifle round (depending on how the beast is lying, or where the dogs are). German hunters are allowed to carry a handgun for those situations but, as a visitor, I can't.
I met a Romanian gentleman at the gunshop last week who lost two fingers when he incautiously approached what he thought was a dead boar. It wasn't dead enough, and it removed his pinkie and ring fingers before expiring. Maybe a pig sticker would have helped...