What are the date formats available in SimpleDateFormat class?
Can anybody let me know about the date formats available in SimpleDateFormat class.
I have gone through api but could not find a satisfactory answer.Any help is highly appreciated.
Solution 1:
Date and time formats are well described below
SimpleDateFormat (Java Platform SE 7) - Date and Time Patterns
There could be n Number of formats you can possibly make. ex - dd/MM/yyyy or YYYY-'W'ww-u or you can mix and match the letters to achieve your required pattern. Pattern letters are as follow.
-
G- Era designator (AD) -
y- Year (1996; 96) -
Y- Week Year (2009; 09) -
M- Month in year (July; Jul; 07) -
w- Week in year (27) -
W- Week in month (2) -
D- Day in year (189) -
d- Day in month (10) -
F- Day of week in month (2) -
E- Day name in week (Tuesday; Tue) -
u- Day number of week (1 = Monday, ..., 7 = Sunday) -
a- AM/PM marker -
H- Hour in day (0-23) -
k- Hour in day (1-24) -
K- Hour in am/pm (0-11) -
h- Hour in am/pm (1-12) -
m- Minute in hour (30) -
s- Second in minute (55) -
S- Millisecond (978) -
z- General time zone (Pacific Standard Time; PST; GMT-08:00) -
Z- RFC 822 time zone (-0800) -
X- ISO 8601 time zone (-08; -0800; -08:00)
To parse:
2000-01-23T04:56:07.000+0000
Use:
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
Solution 2:
Let me throw out some example code that I got from http://www3.ntu.edu.sg/home/ehchua/programming/java/DateTimeCalendar.html Then you can play around with different options until you understand it.
import java.text.SimpleDateFormat;
import java.util.Date;
public class DateTest {
public static void main(String[] args) {
Date now = new Date();
//This is just Date's toString method and doesn't involve SimpleDateFormat
System.out.println("toString(): " + now); // dow mon dd hh:mm:ss zzz yyyy
//Shows "Mon Oct 08 08:17:06 EDT 2012"
SimpleDateFormat dateFormatter = new SimpleDateFormat("E, y-M-d 'at' h:m:s a z");
System.out.println("Format 1: " + dateFormatter.format(now));
// Shows "Mon, 2012-10-8 at 8:17:6 AM EDT"
dateFormatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz");
System.out.println("Format 2: " + dateFormatter.format(now));
// Shows "Mon 2012.10.08 at 08:17:06 AM EDT"
dateFormatter = new SimpleDateFormat("EEEE, MMMM d, yyyy");
System.out.println("Format 3: " + dateFormatter.format(now));
// Shows "Monday, October 8, 2012"
// SimpleDateFormat can be used to control the date/time display format:
// E (day of week): 3E or fewer (in text xxx), >3E (in full text)
// M (month): M (in number), MM (in number with leading zero)
// 3M: (in text xxx), >3M: (in full text full)
// h (hour): h, hh (with leading zero)
// m (minute)
// s (second)
// a (AM/PM)
// H (hour in 0 to 23)
// z (time zone)
// (there may be more listed under the API - I didn't check)
}
}
Good luck!
Solution 3:
java.time
UPDATE
The other Questions are outmoded. The terrible legacy classes such as SimpleDateFormat were supplanted years ago by the modern java.time classes.
Custom
For defining your own custom formatting patterns, the codes in DateTimeFormatter are similar to but not exactly the same as the codes in SimpleDateFormat. Be sure to study the documentation. And search Stack Overflow for many examples.
DateTimeFormatter f =
DateTimeFormatter.ofPattern(
"dd MMM uuuu" ,
Locale.ITALY
)
;
Standard ISO 8601
The ISO 8601 standard defines formats for many types of date-time values. These formats are designed for data-exchange, being easily parsed by machine as well as easily read by humans across cultures.
The java.time classes use ISO 8601 formats by default when generating/parsing strings. Simply call the toString & parse methods. No need to specify a formatting pattern.
Instant.now().toString()
2018-11-05T18:19:33.017554Z
For a value in UTC, the Z on the end means UTC, and is pronounced “Zulu”.
Localize
Rather than specify a formatting pattern, you can let java.time automatically localize for you. Use the DateTimeFormatter.ofLocalized… methods.
Get current moment with the wall-clock time used by the people of a particular region (a time zone).
ZoneId z = ZoneId.of( "Africa/Tunis" );
ZonedDateTime zdt = ZonedDateTime.now( z );
Generate text in standard ISO 8601 format wisely extended to append the name of the time zone in square brackets.
zdt.toString(): 2018-11-05T19:20:23.765293+01:00[Africa/Tunis]
Generate auto-localized text.
Locale locale = Locale.CANADA_FRENCH;
DateTimeFormatter f = DateTimeFormatter.ofLocalizedDateTime( FormatStyle.FULL ).withLocale( locale );
String output = zdt.format( f );
output: lundi 5 novembre 2018 à 19:20:23 heure normale d’Europe centrale
Generally a better practice to auto-localize rather than fret with hard-coded formatting patterns.
About java.time
The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.
To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.
The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.
You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes. Hibernate 5 & JPA 2.2 support java.time.
Where to obtain the java.time classes?
-
Java SE 8, Java SE 9, Java SE 10, Java SE 11, and later - Part of the standard Java API with a bundled implementation.
- Java 9 brought some minor features and fixes.
-
Java SE 6 and Java SE 7
- Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
-
Android
- Later versions of Android (26+) bundle implementations of the java.time classes.
- For earlier Android (<26), a process known as API desugaring brings a subset of the java.time functionality not originally built into Android.
- If the desugaring does not offer what you need, the ThreeTenABP project adapts ThreeTen-Backport (mentioned above) to Android. See How to use ThreeTenABP….