You can't compare the Euro countries to China because the European countries are borrowing in what, in essence, is a foreign currency. For those countries, constant increasing of the debt is hardly sustainable.

China has not that problem. The only danger for China is inflation (that can be controlled with, for instance, taxes), otherwise, the People's Bank of China can buy directly the debt and nothing would happen. In fact, they could just stop emitting debt, but that would be inconvenient for banks and other big investors.

Private and local government debts is a different issue.