BKK-LAX flight with 2 stops inside China

I am planning to take a China Eastern flight from BKK to LAX, which makes 2 stops inside China not exceeding 24 hours - as a matter of fact, the entire flight from BKK to LAX is just about 22 hours. I have no intentions of entering any city in China. Do I need a visa or can I use direct transit? Will I need to go through immigration and customs?