Do I have to apply China visa from Vancouver to Nanjing to Kunming and Bangkok

I'm going to Bangkok from Vancouver to Nanjing to Kunming and Bangkok. I will be layove at Nanjing for 1 hour 40 min for the flight to kunming . And I will be layover 22 hours 45 min at kunming for the flight to Bangkok. So, do I have to apply for the China visa for going through these two Chinese city to Bangkok?