java中的println方法打印Date类型数据

打印Date数据时，调用public void println(Object x) 这个方法，先调用String.valueOf(x)获取String，然后再调用print(String).

Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes print(String) and then println().