I was thinking that today was not the day to tackle Judges 7, since I was pretty tired and didn't have much time, but I see this chapter has mostly charges of absurdity against it in the SAB, which are usually not so difficult to deal with, I think.
So what is absurd here? First, there's this odd selection of Gideon's army by the manner in which people drink water. I've heard it suggested that there may be some significance to the way in which one would hold a sword while drinking from a stream, and that those who drink "with his tongue, as a dog lappeth" are showing greater alertness for a possible approaching enemy. I could see the value of that, although I have also heard some debates about whether this really makes any sense. My own take on it is from the context of the verses before: God wants Gideon to have a small army, so that He will get the credit. Remember, in the grand scale of things, the purpose of this battle is not just to free the Israelites from the oppression of the Midianites, but to turn them back to faith in God. There were 10,000 men when they went to have a drink, and God chose 300 to stay; that means 9,700 were turned away! I think this was just an arbitrary selection to get the smaller group, which turned out to be considerably smaller.
Verse 12 is also tagged for absurdity, though I think we're talking about hyperbole here, and what we're saying is that there are too many camels to count. There's something else noteworthy about this verse in respects to the issue of the number of Midianites. In this verse, it says "Midianites and Amalekites". It is quite possible that this is actually a coalition of several nations that happens to be led by the Midianites, which would explain the number of them a bit better.
The next few verses, despite being marked as absurd, are really quite clear and straightforward to me. It's made clear that the Midianites have been supernaturally caused to be very afraid of the idea that they are about to be attacked by a massive army. That night, the men arrive with trumpets, pitchers and lamps. Here's how it works: the lamps are inside pitchers so that they won't be spotted coming, and so that once the time comes to reveal themselves, they can whip out their lamps and smash the pitchers, making a sudden blaze of light accompanied by a crashing noise and the sound of 300 trumpets. Normally, an army would not have every man carry a torch or a trumpet, so the Midianites are to be confused by the illusory sights and sounds of a huge army created by just a relatively small group of men. In the resulting confusion and panic, members of the Midianite army either run away or mistakenly fight each other. Gideon's army of 300 hardly have to draw their swords to attain victory! Violent? Yes, but it's war, and these men are an occupying force.
The chapter ends with the capture and killing of two "princes" of Midian; it's a nasty business, yes, but my caveat here is that once again, it's war, and there's also no particular indication that the Bible condones the manner in which they were killed.