Do I need to register at local police station?

I am planning to fly from Madrid to Shanghai via Moscow, then stay 5 days in Shanghai and then fly from Shanghai to Melbourne via Kuala Lumpur. Do I need to register at local police station within 24 hours upon arrival? I was considering staying over for those 4 nights with a host from couch surfing platform. Would he need to accompany me to the police station?
In any case, I arrive quite late to Shanghai so I may stay at a hotel close by the airport for the first night and then move to the host house. In such a case, would the hotel register me, even if I am only staying there for one night?

Thanks in advance!
Jaime.