Java SimpleDateFormat Class

java.text.SimpleDateFormat is a concrete implementation of DateFormat class for formatting and parsing dates as per the passed formatting pattern. For example

SimpleDateFormat sdf = new SimpleDateFormat("EEEE, MMMM dd, yyyy");

shows the formatted date in the form- Wednesday, July 15, 2019

Table of contents

Java SimpleDateFormat constructors
Java SimpleDateFormat Date and Time patterns
Formatting date using SimpleDateFormat examples
Parsing date using SimpleDateFormat

Java SimpleDateFormat constructors

There are four constructors in SimpleDateFormat class.

SimpleDateFormat()- Constructs a SimpleDateFormat using the default pattern and date format symbols for the default FORMAT locale.
SimpleDateFormat(String pattern)- Constructs a SimpleDateFormat using the given pattern and the default date format symbols for the default FORMAT locale.
SimpleDateFormat(String pattern, DateFormatSymbols formatSymbols)- Constructs a SimpleDateFormat using the given pattern and date format symbols.
SimpleDateFormat(String pattern, Locale locale)- Constructs a SimpleDateFormat using the given pattern and the default date format symbols for the given locale.

Java SimpleDateFormat Date and Time patterns

Date and time formats are specified by date and time pattern strings. Following list shows the pattern letters that are used with SimpleDateFormat.

Letter	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
Y	Week year	Year	2009; 09
M	Month in year (context sensitive)	Month	July; Jul; 07
L	Month in year (standalone form)	Month	July; Jul; 07
w	Week in year	Number	27
W	Week in month	Number	2
D	Day in year	Number	189
d	Day in month	Number	10
F	Day of week in month	Number	2
E	Day name in week	Text	Tuesday; Tue
u	Day number of week (1 = Monday, ..., 7 = Sunday)	Number	1
a	Am/pm marker	Text	PM
H	Hour in day (0-23)	Number	0
k	Hour in day (1-24)	Number	24
K	Hour in am/pm (0-11)	Number	0
h	Hour in am/pm (1-12)	Number	12
m	Minute in hour	Number	30
s	Second in minute	Number	55
S	Millisecond	Number	978
z	Time zone	General time zone	Pacific Standard Time; PST; GMT-08:00
Z	Time zone	RFC 822 time zone	-0800
X	Time zone	ISO 8601 time zone	-08; -0800; -08:00

Rules that are followed for the patterns are as follows-

1. For text if the number of pattern letters is 4 or more full form is used otherwise a short or abbreviated form is used if available. For example, a EEEE pattern can display full name of weekday like Wednesday and a EEE pattern can display Wed.

2. For formatting, the number of pattern letters is the minimum number of digits, and shorter numbers are zero-padded to this amount.

For numbers, the number of times a pattern letter is repeated determines the minimum number of digits, for shorter numbers zero-padding is done if required. For example, hh:mm:ss shows 03:45:15, but h:m:s displays the same time as 3:45:15.

3. For month, If the number of pattern letters is 3 or more, the month is interpreted as text; otherwise, it is interpreted as a number.

Formatting date using SimpleDateFormat examples

After creating an instance of SimpleDateFormat with the specified pattern, using the format() method you can format the date.

import java.text.SimpleDateFormat;
import java.util.Date;

public class FormatDate {

  public static void main(String[] args) {
    // For date in format 2019.07.04 AD at 11:08:54 IST
    formatDate("yyyy.MM.dd G 'at' HH:mm:ss z");
    // For date in format Mon, Oct 7, '19
    formatDate("EEE, MMM d, ''yy");
    // For date in format Monday, October 07, 2019
    formatDate("EEEE, MMMM dd, yyyy");
    // For time in format 07 o'clock PM, India Standard Time
    formatDate("hh 'o''clock' a, zzzz");
    // For time in 24 Hr format 19:41:59:635 PM
    formatDate("HH:mm:ss:SSS a");
    // For date-time in format 2019-10-07T19:27:38.571+0530
    formatDate("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
    // For date in format 05/08/2016
    formatDate("MM/dd/yyyy");
    // For date in format 07/10/2019 19:29:40 PM
    formatDate("dd/MM/yyyy HH:mm:ss a");
    // For date in format 07/10/2019 19:29:40 PM
    formatDate("dd/MMM/yyyy GGG HH:mm:ss:SSS a");
  }
	
  private static void formatDate(String pattern){
    Date dt = new Date();
    // Create date format as per specified pattern
    SimpleDateFormat sdf = new SimpleDateFormat(pattern);
    String formattedDate = sdf.format(dt);
    System.out.println("Formatted Date- " + formattedDate +
              " for Pattern: " + pattern); 
  }
}

Output

Formatted Date- 2019.10.07 AD at 19:41:59 IST for Pattern: yyyy.MM.dd G 'at' HH:mm:ss z
Formatted Date- Mon, Oct 7, '19 for Pattern: EEE, MMM d, ''yy
Formatted Date- Monday, October 07, 2019 for Pattern: EEEE, MMMM dd, yyyy
Formatted Date- 07 o'clock PM, India Standard Time for Pattern: hh 'o''clock' a, zzzz
Formatted Date- 19:41:59:635 PM for Pattern: HH:mm:ss:SSS a
Formatted Date- 2019-10-07T19:41:59.638+0530 for Pattern: yyyy-MM-dd'T'HH:mm:ss.SSSZ
Formatted Date- 10/07/2019 for Pattern: MM/dd/yyyy
Formatted Date- 07/10/2019 19:41:59 PM for Pattern: dd/MM/yyyy HH:mm:ss a
Formatted Date- 07/Oct/2019 AD 19:41:59:641 PM for Pattern: dd/MMM/yyyy GGG HH:mm:ss:SSS a

Parsing date using SimpleDateFormat

Using parse() method of SimpleDateFormat you can convert String to a java.util.Date instance.

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class ParseDate {
  public static void main(String[] args) {
    try {
      parse("dd/MM/yyyy", "09/08/2019");
      
      parse("MM-dd-yyyy", "09-08-2019");
      // Date will default to epoch (January 1, 1970)
      parse("HH:mm:ss", "20:04:19");
      
      parse("MM-dd-yyyy HH:mm:ss", "09-08-2019 20:04:19");
    }catch (ParseException e) {
      System.out.println("Error while parsing- " + e.getMessage());
    }
  }
	
  private static void parse(String pattern, String dateTime) throws ParseException{
    // Create date format as per specified pattern
    SimpleDateFormat sdf = new SimpleDateFormat(pattern);
    Date dt = sdf.parse(dateTime);
    System.out.println("After parsing- " + dt);
  }
}

Output

After parsing- Fri Aug 09 00:00:00 IST 2019
After parsing- Sun Sep 08 00:00:00 IST 2019
After parsing- Thu Jan 01 20:04:19 IST 1970
After parsing- Sun Sep 08 20:04:19 IST 2019

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January 2, 2023