This is most likely not the most efficient way, but one way would be to get into a fight with an NPC that does the damage type you wish to check, i.e. energy. Then, after a successful attack by that NPC, go to your Journal tab, select Messages, then the Feedback tab. There, it will say something along the lines of "(your name) resists xx points of damage". That will tell you exactly what your level of resistance is.
- Star Admiral