First of all, China are less than happy about the current situation and they want it solved, peacefully, just the consequences for the global energy market is of annoyance to China as it means increased costs. Secondly, prior to all of this Ukraine was a bigger trade partner to China than Russia, and China depend on a well functioning global market. Tanking the global market, sure as shit isn't something they're keen on and there's nothing at all right now that suggests Russia is even going to compensate for the increased costs in the energy market.