Adopting a pet in China

Not recommend to keep a dog in China.
Most of Chinese still thinks  "dog is animal, not family member"
1. They walk dogs without rope. So many dogs lost on the street then caught and sold to Guangdong as food.
2. Low medical degree. Doctors sell drugs and supplement mostly instead of normal treatment
3. 99% Chinese does not clean shit when walking dog. It cause negative impression when others see someone who is walking dogs

Cat is ok since you keep it at home. Dog is not recommend yet if you don't want to see it suffers.

lol

I adopted a dog less than a year ago, I am not in China right  now (hope to be by the end of this month), and my is with me and we'll be back together. 
I took my dog from a rescue group Furry Friends, you can search for them in WeChat. You can also foster a dog for some time is you are not sure if you are really able to take it. There were nor special formalities except for the agreement you have to sign. It's mostly about your promise to be nice to the dog. 
There are a lot of rescue groups in Shanghai and a lot of pets who were abandoned, so I really cannot support shopping for pets here. 

Pet-sitting options are good here in Shanghai. There is a company SpareLeash that helps with pet-sitting. I don't use their services  as we have an independent dog-sitter who is amazing, but many of my friends do and are very happy.