Sludge, certainly a catapult is one way of doing it, but the Harrier, both RN and USN, uses (used) the "ski-jump". In the Falklands nastiness it was the only way the Harriers were launched, and they were fully loaded.
In fact there is a video of the F-35 using a ski jump on the USS Wasp. The difference is the F-35, because of its STOVL capability has a lot more engineering (i.e weight) than the F-18 or it's Chinese equivalent.
It is interesting that the Chinese use coloured shirts (imitation is the sincerest form of flattery). Granted the film clip is a great propaganda boost but I think the Chinese are a lot closer to being a fully operational force than many would like to admit.
The US offered the Brits a carrier with steam catapults but they turnned it down. IMO it would have changed the war dramatically as an E2C would have been the best answer to all these incoming flights to setup good intercepts. Thats the advantage of a decent carrier with catapults is not only the strike aircraft but also the support aircraft which give you better and constant round the clock coverage of the area. IMO putting a radar on a Seaking and using that as an AWACs is not a smart idea.