Guns don't kill people. Doctors kill people.
But yeah, in all seriousness, owning a gun should work similar to being able to drive a car. You should have to pass a written exam and a psychiatric evaluation to prove you are of sound mind to own and handle one. Still, in most massacres, the shooter wasn't mentally stable and/or was using guns that weren't theirs. So while this won't eliminate the problem, it should remedy it at least a little.
I also think the China attack is a bad example to compare the shootings to. A knife could cause injury, but it has to hit particular organs for it to be fatal. Had the attacker used a stronger weapon like a sledgehammer, pickaxe, power tool, or anything else you could easily buy at Lowe's or Home Depot without a permit, there would have been many more casualties and injuries. At the same time, there are a LOT of things that could easily be turned into weapons if used the wrong way. If you use gun laws to try and control the distribution of guns, it only means people are just going to find creative ways around it. Such as using explosives. Or gasoline and fire. Hate to say it, but the attack on Aurora and Newtown could have easily been done via arson or gas using everyday items and be just as, if not more, lethal than the shootings. You'd be surprised how easy it is to make your own Molotov cocktails, and that's just a very mild example. Let's not forget that Ted Kaczynski, Jack the Ripper, and the extremists that were responsible for the 9/11 attacks didn't need guns to kill and do extreme amounts of damage.
I won't deny, guns do make it easier to kill people and they are often over-glamorized and their very presence makes some people react in bad ways. But in essence, the people that BADLY want guns will get their hands on them one way or another. It's a matter of crime control, not gun control.
Those who want to kill will find ways to kill, whether it's through guns or something else. Banning guns just gives the rest of us that don't have access to the anarchist's cookbook one less thing to defend ourselves with.