为什么date.toString（）两次打印相同的结果

Question

When I call the method date.toString() twice, I have the same result, even though there is a two second interval. I think the second time should be 2s more than first time.

Program for example:

Date date = new Date();
System.out.println(date.toString());
System.out.println("----------");
Thread.sleep(2000);
System.out.println(date.toString());

The output is

Sat Oct 17 17:54:39 CST 2015
----------
Sat Oct 17 17:54:39 CST 2015

Answer 1

Quoting the Javadoc of the constructor of Date (emphasis mine):

Allocates a Date object and initializes it so that it represents the time at which it was allocated , measured to the nearest millisecond.

As such, the Date that is printed is the date when the object was created. Since you are printing the same Date object, it will be the same output.

Date date = new Date();
System.out.println(date.toString());
System.out.println("----------");
Thread.sleep(2000);
date = new Date(); // instantiate a new Date here
System.out.println(date.toString());

Output on my machine:

Sat Oct 17 12:09:16 CEST 2015
----------
Sat Oct 17 12:09:18 CEST 2015

Answer 2

try this...

Date date = new Date();
System.out.println(date.toString());
System.out.println("----------");
Thread.sleep(2000);
date = new Date();
System.out.println(date.toString());

just initiate again the "date" before print for the second time