Okay, but I read on some law school websites that if you don't have a teacher rec and you haven't been out of school for a long time, they'll really look at your app weird and wonder why you can't get a prof to reccomend you. So what do you do then?
You should definitely to try get an academic recommendation; like you said, if you don't have a teacher recommendation and you haven't been out of school for a while, then AdComs will likely wonder why. If you haven't become close with any professor, that's not necessarily an impediment to getting an academic rec (or recs). Think about who else knows you academically; it's very likely that TAs in various classes know you well academically, and can speak to your abilities. Consider asking one of them.
In any case, even if you feel the person knows you well, you should still approach them with the mentality that they don't, and provide them with all the information they'll need to write an informed letter: A copy of the résumé you'll be submitting to law schools, a copy of your personal statement, a copy of any major papers you wrote for the class the prof (or TA) taught. In addition, plan to not simply drop these things off and say "Please write me a letter and let me know if you have any questions"--instead, plan on meeting with the recommender for at least an hour to discuss what you would like out of the recommendation, any specific highlights you'd like the recommender to hit, which schools you're applying to, what your law school and career goals and ambitions are, etc. This will make sure that the recommender is as informed as possible about you and your plans, and can speak intelligently about them.
So see, even if you DON'T have a really close relationship with a prof, you can still create an INFORMED relationship with a prof that will yield a good, solid letter (even if it won't be the same as a letter from someone that's known you for years). You will definitely have to try to create a relationship though.