Can I stay in Pudong Airport overnight (10pm-4am)?

My flight leaves at 4:20am. I am currently living in Suzhou and won't have money for a taxi when I get to Shanghai. I planned to take the subway to PVG. However, since the subway stops around 10:00pm, I'll have to arrive at the airport no later than that. Will I be able to stay in the airport overnight, from 10:00pm to 4:20am?