Do I qualify for a 144 hours visa

Hi!
I'm currently studying in China on a single-entry visa. It is not possible for me to apply for a double-entry anymore since my semester is already over. For my final trip I would like to go to Cambodia, but my flight back home will departure from Shanghai. My itinerary will be Shanghai- Cambodia, Cambodia-Shanghai, Shanghai-Germany. Is it possible for me to use the 144 hours free transit?