i am an army officer with a pakistani official passport.i want to visit china.what r the requirement

i just read on ur website that official pakistani passport holders r exempted from visa for mainland china 30 days and hong kong 14 days so will i be given visa once i reach china or will i get it from chinese embassy in islamabad.moreover as i am an army officer and i have got ex pakistan leave so what all documents will be required to show like NOC etc.