There are a number of comments indicating that China has no chance in a trade war with the USA.  Let's see what is at stake for China.  China's exports are about 20% of their GDP. Then the USA takes 18% of those exports. So, that's less than 4% of GDP.   At the other end, GM sells more cars in China than they do in the USA.  China has also threatened to cancel orders from Boeing.  They also hold $1.119 trillion dollars worth of US treasury bonds.  And finally, much of America's working class poor will be hard pressed if prices at Wal-Mart increase by the 30% tariff that Trump has threatened.  
It all sounded good when the campaign promises were made and no one thought about the implications.