I think it depends on who you approach. The place I went to in Chengdu was actually owned by a foreigner. You would get measured. Then he sourced fabric from Hong Kong, had the pieces made there, then made second and third fittings in person. Shoes were made locally, with leather sourced from Hong Kong as well.

I'm not sure if it would be possible to order a completely bespoke tailored suit online. If you gave them your measurements, you probably could get a suit, that was semi-tailored (similar to off-the-shelf suits). You'd still need to get final adjustments made. But it still wouldn't be completely fitted 100% to you and your body.