About the date format
Date and time formats are specified by the date and time pattern strings. Within the date and time pattern strings, unquoted letters from 'A' to 'Z' and from 'a' to 'z' are interpreted as pattern letters representing the components of a date or time string. Text can be quoted using single quotes (') to avoid interpretation. "''" represents a single quote. All other characters are not interpreted, they are simply copied into the output string during formatting or matched against 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 |
|---|---|---|---|
|
G |
Era designator |
Text |
AD |
|
y |
Year |
Year |
1996; 96 |
|
M |
Month in year |
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 in week |
Text |
Tuesday; Tue |
|
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 |
Pacific Standard Time; PST; GMT-08:00 |
|
|
Z |
Time zone |
RFC 822 time zone |
-0800 |
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, regardless 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 is needed to separate two adjacent fields.
Year
If the formatter uses the Gregorian calendar, the following rules apply:
-
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. This means that 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"), SimpleDateFormat must interpret the abbreviated year relative to some century. It does this 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, 1997, the string "01/11/12" is interpreted as Jan 11, 2012 while the string "05/04/64" is interpreted as May 4, 1964. During parsing, only strings consisting of exactly two digits, as defined by Character.isDigit(char), are parsed into the default century. Any other numeric string is interpreted literally. This means that "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.
Otherwise, calendar-system specific forms are applied. For both formatting and parsing, if the number of pattern letters is 4 or more, a calendar specific long form is used. Otherwise, a calendar specific short or abbreviated form is used.
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 the same as for general time zones.
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 |