Short answer:
1) There's no such thing as a green laser diode. Without driving you crazy with a technical explanation, green lasers are really Infrared lasers shot through a magic crystal to become green.
2) So you'll almost always find them assembled as working laser modules that INCLUDE a driver attached to the IR diode, which is then attached to the crystal, lens, etc.
3) You'd probably only need an LM317 driver for a green laser if you destroyed the factory driver that was attached to the IR diode.
4) If that's the case, figure out how much current the IR diode is meant to take (maybe measure a working driver? who knows). Then do this calculation (1.25 / current in mA)
5) You'll get a number. That's the resistance in Ohms that you want to use for an LM317 DDL circuit's resistor. Google LM317 DDL and you'll find the basic circuit diagram to use.