Is the Visa free in Shanghai

Hi,
I am traveling from New York city to Okinawa Japan, stoping in SH for 16 hrs on my way to japan and 19 hrs on my return. I am looking to leave airport and do some sightseeing. Do I need to obtain a Visa before hand or will I be able to use my passport at the airport in SH for a Free Visitor Visa?

Thanks for your help!