Cruise entering Beijing, leaving and re-entering Dlian, leaving and re-entering Shanghai

We are Australian and will be sailing into Beijing on a cruise, staying for 48 hours, then leaving and sailing to Dalian for 24 hours, leaving and sailing to Shanghai for another 48 hours before leaving for Hong Kong. Total hours in and out of China is less than 144 hours.
Can we use the 144 hour visa facility?
Or do we need to re-apply for visa on each arrival?
Or do we need to get visas before departure from Australia?
Also, can we get visas at the port of arrival (shipping port)?