创建 2 个线程，实现：按下键盘上“1”键时由线程 1 打印“Hello”，按下键盘上“2”键 时由线程 2 打印“World”，按“0”键时程序-Create two threads to achieve: press on the keyboard " 1" key Printing by the thread 1 " Hello" , press on the keyboard " 2" key to print by a threa