Dimwitted and somewhat easy to defeat, Battle Droids are the enemy you will fight the most when you play as either Anikin Skywalker or Obi Wan Kanobi.
Though it only takes a few stokes of your lightsaber to cut them down, the dimwitted 'bots may overwhelm you with sheer numbers. Concentrate on them one at a time, or, if you don't have enough life force to battle, run away, pressing the jump key to dodge their blaster fire. Once out of range they will stop attacking.