Do I need a visa? Can I go to 2 different Chinese cities without a visa.

I have a flight from Vancouver to Shanghai and then my next flight is the following morning from Shanghai to Auckland. There is a 26 hour delay in between the flights that is causing this. I have no problem with getting the hotel that is located inside the airport for this. My main question is, I have a return flight from Auckland to Shanghai, with a 12 hour layover in Shenzhen, before I proceed to Vancouver after 2 days (48 Hours).