How to get year, month, day, hours, minutes, seconds and milliseconds of the current moment in Java?

Question

I would like to have them as strings.

Answer 1

Look at the API documentation for the java.util.Calendar class and its derivatives (you may be specifically interested in the GregorianCalendar class).

Answer 2

Make use of java.util.Calendar.

Calendar now = Calendar.getInstance();
int year = now.get(Calendar.YEAR);
int month = now.get(Calendar.MONTH); // Note: zero based!
int day = now.get(Calendar.DAY_OF_MONTH);
int hour = now.get(Calendar.HOUR_OF_DAY);
int minute = now.get(Calendar.MINUTE);
int second = now.get(Calendar.SECOND);
int millis = now.get(Calendar.MILLISECOND);

System.out.printf("%d-%02d-%02d %02d:%02d:%02d.%03d", year, month + 1, day, hour, minute, second, millis);

This prints as of now (I'm at GMT-4):

2010-04-16 11:15:17.816

To convert an int to String, make use of String#valueOf().

If your intent is after all to arrange and display them in a human friendly format, then I'd suggest to use java.text.SimpleDateFormat instead. Click the link, you'll see a table of patterns letters. Several examples:

Date now = new Date(); // java.util.Date, NOT java.sql.Date or java.sql.Timestamp!
String format1 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ").format(now);
String format2 = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss Z").format(now);
String format3 = new SimpleDateFormat("yyyyMMddHHmmss").format(now);

System.out.println(format1);
System.out.println(format2);
System.out.println(format3);

Which yields:

2010-04-16T11:15:17.816-0400
Fri, 16 Apr 2010 11:15:17 -0400
20100416111517

Answer 3

Switch to joda-time and you can do this in three lines

DateTime jodaTime = new DateTime();

DateTimeFormatter formatter = DateTimeFormat.forPattern("YYYY-MM-dd HH:mm:ss.SSS");
System.out.println("jodaTime = " + formatter.print(jodaTime));

You also have direct access to the individual fields of the date without using a Calendar.

System.out.println("year = " + jodaTime.getYear());
System.out.println("month = " + jodaTime.getMonthOfYear());
System.out.println("day = " + jodaTime.getDayOfMonth());
System.out.println("hour = " + jodaTime.getHourOfDay());
System.out.println("minute = " + jodaTime.getMinuteOfHour());
System.out.println("second = " + jodaTime.getSecondOfMinute());
System.out.println("millis = " + jodaTime.getMillisOfSecond());

Output is as follows:

jodaTime = 2010-04-16 18:09:26.060

year = 2010
month = 4
day = 16
hour = 18
minute = 9
second = 26
millis = 60

Answer 4

Calendar now = new Calendar() // or new GregorianCalendar(), or whatever flavor you need

now.MONTH now.HOUR

etc.