tourist stay for 4 months?(multiple entry?)

i would like to visit china for a longer period of time(4 months) to travel.

i am willing to fly out of the country (or HongKong) if needed.

Can i apply for a tourist visa?
will they allow me to stay for 4 months?
or
will I have a stay of 30 days and then: Am I Allowed to re-enter the country?

My purpose is go to Xiamen and stay for one month and after this i would like to travel on mainland china for three months.