Am I entitled for 72 hrs visa free? Do I need to do something in advance?

I am an Italian citizen. I will be travelling from Germany to Shanghai (PVG), where I will stay for less than 72 hours. Then I will fly to Malaysia with a different Airline. After a couple of weeks I will repeat the same route back: Malaysia to Shanghai (PVG), where I will stay for less than 24 hours and then I will fly to Germany back.
My understanding is that I should be entitled for 72 hrs free transit type (1st leg of the trip) and for direct transit (2nd leg of the trip). Is it correct?
Can I get the permits directly from the immigration officer at the airport just with the onward tickets?
Many thanks.