The Grand Hyatt is more or less equal distance from the "Lujiazui" and "Dongchang Road" stops on line 2 of the Shanghai metro. In both cases, maybe 400 - 500 meters.

However, this being China, it's not the same cozy walk as elsewhere but noisy and dusty construction sites, frantic traffic and around the SWFC, the notorious laser gadget salespeople who like nothing more than pointing their laser beams in the eye of the unsuspecting laowai.

So maybe better take a taxi when arriving from the airport. Without luggage the metro is rather pleasant to use.