Zombies don't magically spring up out of nowhere, even in the most extreme fictional scenarios as if that happens there is no hope.
If we go with the traditional zombie plague transmission method of bites or scratches, then there will be front lines and safe zones.
The key is when a government realises it cannot save everyone and cuts its losses, sacrificing hundreds of thousands or even millions to save the rest. In that respect, China as a civilization would be better placed than most because its leaders tend to look at things in terms of the big picture. That means that their first instincts would be to organise logistics, establish safe zones and draw up long term battle plans rather than making speaches or trying to create photo ops as some leaders' instincts may cause them to do.
As for soldiers staying at their posts, well again, that's not a new problem and all militarise go to great lengths to indoctrinate its raw recruits into obeying orders without question or hesitation when they train them up to be soldiers.
If that training fails, the PLA has MPs like all other armies, and political officers/commissars who will make sure discipline is maintained.
If your civilisation is reduced to scattered bands of survivors scavenging what they can form the bones of dead cities, then your civilisation is already lost, and its only a matter of time before everyone gets turned or killed.
The only way any civilisation, or the human race for that matter, can survive a zombie apocalypse is if some form or organised government survives to direct and focus the efforts of the survivors into establishing safe zones and adapt industry to produce the food, clean water, medical supplies, weapons and tools needed to face down and then turn back the undead tide.
In a way, I think the Chinese government is missing out on a huge opportunity with this genre, since it could quite plausibly cast China and Russia as the ones most ready and able to do that under the strong unified leadership of the central government, and contrast that to the indecisiveness and short sightedness of others that end up dooming their people.
But in order to pull that off, they will have to show the ruthless efficiency and cold hearted calculations needed to focus on the big picture, and I'm not too sure the Chinese government want to promote such an image of itself, even if it secretly counts that as one of its key strengths.