Date and Time Patterns

This section describes how to use Java date/time patterns for parsing and formatting times and dates. See http://docs.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html for more detail.

Pattern Letters

You specify date and time formats using pattern letters. Date and time pattern strings use unquoted letters from ‘A’ to ‘Z’ and from ‘a’ to ‘z’, with each letter representing a formatting element.

Note: if you include other characters, they will be incorporated into the output string during formatting or compared to the input string during parsing.

The following pattern letters are defined (all other characters from ‘A’ to ‘Z’ and from ‘a’ to ‘z’ are reserved):

Letter Date or Time Component Presentation Examples
y Year Year yyyy; yy 2018;18
Y Week year Year YYYY; YY 2009; 09
M Month in year Month MMM;MM;MM July; Jul; 07
w Week in year Number ww; 27
W Week in month Number W 2
D Day in year Number DDD 321
d Day in month Number dd 10
F Day of week in month Number F 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

You determine the exact presentation by repeating pattern letters, along the lines of YYYY. Pattern letters are usually repeated, as their number determines the exact presentation:

Text

For formatting, if the number of pattern letters is 4 or more, the full form is used; otherwise a short or abbreviated form is used if available. For parsing, both forms are accepted, independent of the number of pattern letters.

Number

For formatting, the number of pattern letters is the minimum number of digits, and shorter numbers are zero-padded to this amount. For parsing, the number of pattern letters is ignored unless it’s needed to separate two adjacent fields.

Year

For formatting, if the number of pattern letters is 2, the year is truncated to 2 digits; otherwise it is interpreted as a number

For parsing, if the number of pattern letters is more than 2, the year is interpreted literally, regardless of the number of digits. So using the pattern “MM/dd/yyyy”, “01/11/12” parses to Jan 11, 12 A.D.

For parsing with the abbreviated year pattern (“y” or “yy”), the formatting codes and rules are the same as for the SimpleDateFormat java class: the abbreviated year is interpreted relative to some century by adjusting dates to be within 80 years before and 20 years after the time the SimpleDateFormat instance is created. For example, using a pattern of “MM/dd/yy” and a SimpleDateFormat instance created on Jan 1, 2018, the string “01/11/12” would be interpreted as Jan 11, 2012 while the string “05/04/64” would be interpreted as May 4, 1964.

During parsing, only strings consisting of exactly two digits, as defined by Character.isDigit(char ch), will be parsed into the default century. Any other numeric string, such as a one digit string, a three or more digit string, or a two digit string that isn’t all digits (for example, “-1”), is interpreted literally. So “01/02/3” or “01/02/003” are parsed, using the same pattern, as Jan 2, 3 AD. Likewise, “01/02/-3” is parsed as Jan 2, 4 BC.

Month

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

General Time Zone

Time zones are interpreted as text if they have names. For time zones representing a GMT offset value, the following syntax is used:

GMTOffsetTimeZone:
GMT Sign Hours : Minutes
Sign: one of
\+ -
Hours:
Digit
Digit Digit
Minutes:
Digit Digit
Digit: one of
0 1 2 3 4 5 6 7 8 9

Hours must be between 0 and 23, and Minutes must be between 00 and 59. The format is locale independent and digits must be taken from the Basic Latin block of the Unicode standard.

For parsing, RFC 822 time zones are also accepted.

RFC 822 time zone

For formatting, the RFC 822 4-digit time zone format is used:

RFC822TimeZone:
Sign TwoDigitHours Minutes
TwoDigitHours:
Digit Digit

TwoDigitHours must be between 00 and 23. Other definitions are as for general time zones.

For parsing, general time zones are also accepted.

SimpleDateFormat also supports ‘‘localized date and time pattern’’ strings. In these strings, the pattern letters described above may be replaced with other, locale dependent, pattern letters. SimpleDateFormat does not deal with the localization of text other than the pattern letters; that’s up to the client of the class.

Examples

The following examples show how date and time patterns are interpreted in the U.S. locale. The given date and time are 2001-07-04 12:08:56 local time in the U.S. Pacific Time time zone.

Date and Time Pattern Result
“yyyy.MM.dd G ‘at’ HH:mm:ss z” 2001.07.04 AD at 12:08:56 PDT
“EEE, MMM d, ‘‘yy” Wed, Jul 4, ‘01
“h:mm a” 12:08 PM
“hh ‘o'‘clock’ a, zzzz” 12 o’clock PM, Pacific Daylight Time
“K:mm a, z” 0:08 PM, PDT
“yyyyy.MMMMM.dd GGG hh:mm aaa” 02001.July.04 AD 12:08 PM
“EEE, d MMM yyyy HH:mm:ss Z” Wed, 4 Jul 2001 12:08:56 -0700
“yyMMddHHmmssZ” 010704120856-0700
“yyyy-MM-dd’T’HH:mm:ss.SSSZ” 2001-07-04T12:08:56.235-0700

Pattern Letters in Alphabetic Order

The same pattern letters shown at first, above, in Date or Time Component order are shown below in alphabetic order for easy reference.

Pattern Letter Date or Time Component Presentation as text or number Examples
a Am/pm marker Text PM
D Day in year Number 189
d Day in month Number 10
E Day in week Text EE=Tu; EEE=Tue; EEEE=Tuesday
F Day of week in month Number 2
G Era designator Text AD
H Hour in day (0-23) Number 0
h Hour in am/pm (1-12) Number 12
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
M Month in year Month July; Jul; 07
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
w Week in year Number 27
W Week in month Number 2
y Year Year 1996; 96
z Time zone General Pacific Standard Time; PST; GMT-08:00 |
Z Time zone RFC -0800