Why are different long values converted into the same date/time?

问题

public static void getTime() {
    SimpleDateFormat sdf = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss");
    Time t1 = new Time(Long.parseLong("1369213412435"));
    Time t2 = new Time(Long.parseLong("1369213412245"));
    System.out.println(sdf.format(t1));
    System.out.println(sdf.format(t2));
}

Why does the above code prints,

2013-05-22 17:03:32
2013-05-22 17:03:32

回答1:

The two dates differ only by milliseconds (435 or 245), which you ignore in your format.

Use:

 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");

to see the different values.

回答2:

The only difference is in the milliseconds (435 vs 245).

回答3:

The two dates are differed by milliseconds i.e. 435 and 245.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");

This will do.

回答4:

Use :

 SimpleDateFormat sdf = new SimpleDateFormat(
                    "yyyy-MM-dd HH:mm:ss:SSS");

and you will see the difference in the milliseconds part.

回答5:

Apart from the millisecond parts there are certain cases where two long values can provide same date.

i.e. below two long values have same millisecond and are different

1458065184000
1458021984000

If you use dd-MM-yyyy hh:mm:ss SSS then it will give you the same result.

Catch here is hh (12 hr format) vs HH (24 hr format).

Using this will give the accurate result dd-MM-yyyy HH:mm:ss SSS

来源：https://stackoverflow.com/questions/16708785/why-are-different-long-values-converted-into-the-same-date-time

标签

java

date

syntax

simpledateformat