I don't think China is gunning for us just yet; however, if we accept their "goods" and allow them to help finance our debt (we are) and then we effectively devalue the dollar by printing more (we're doing that too IMO), thus repaying the debt with cheaper dollars, how good a trading partner are we?
The Chinese are always looking for other markets.

As for them getting hit back by the worlds only remaining military superpower, that presumes we know who launched the attack. With a sea-based attack from a merchant ship, the gun isn't smoking. It's really very Tom Clancy'ish, but I can see this happening and while we'd know it came from the sea, our ability to determine specifically which platform did it would be muddied by the lack of sensors after the strike. Plausible denial would rule and with the Chinese offering aid and friendship following the attack, would we bite the hand that's feeding us?

Diabolical. . . we'd be blaming Iran or N. Korea with no firm evidence and the real culprit would be off-loading supplies in Long Beach.