Transit visa needed for Vietnamese citizen?

Hello, I am planning to buy a flight ticket, but I want to make sure that I don't need to get a transit one or something like that.

So I'm flying from Hanoi, Vietnam to Tokyo, Japan. My first layover is in Hong Kong. From Hong Kong, I'll be flying to Shanghai Pudong Airport. There my layover is about 15 hours. The next day I will fly out of Hongqiao airport.

Do I need a Chinese transit type of some sort? My stay in China is less than 24 hours and I'm a Vietnamese citizen. I just want to make sure. Thank you!

Lam