SimpleDateFormat is a concrete class for formatting and parsing dates in a locale-sensitive manner. It allows for formatting (date -> text), parsing (text -> date), and normalization.
SimpleDateFormat allows you to start by choosing any user-defined patterns for date-time formatting. However, you are encouraged to create a date-time formatter with either
DateFormat. Each of these class methods can return a date/time formatter initialized with a default format pattern. You may modify the format pattern using the
applyPattern methods as desired. For more information on using these methods, see
Date and Time Patterns
Date and time formats are specified by date and time pattern strings. Within date and time pattern strings, unquoted letters from
'Z' and from
'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’re 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
'Z' and from
'z' are reserved):
Letter Date or Time Component Presentation Examples
Era designator Text
Month in year Month
Week in year Number
Week in month Number
Day in year Number
Day in month Number
Day of week in month Number
Day in week Text
Am/pm marker Text
Hour in day (0-23) Number
Hour in day (1-24) Number
Hour in am/pm (0-11) Number
Hour in am/pm (1-12) Number
Minute in hour Number
Second in minute Number
Time zone General time zone
Pacific Standard Time;
Time zone RFC 822 time zone
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”),
SimpleDateFormatmust 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
SimpleDateFormatinstance is created. For example, using a pattern of “MM/dd/yy” and a
SimpleDateFormatinstance created on Jan 1, 1997, 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), 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:
: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
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.
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
"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
Note: This example formats dates using the default locale (which, in the author’s case, is Locale.ENGLISH). If the example is run in a different locale, the text (e.g., month names) will not be the same.
// The year
formatter = new SimpleDateFormat("yy"); // 02
formatter = new SimpleDateFormat("yyyy"); // 2002
// The month
formatter = new SimpleDateFormat("M"); // 1
formatter = new SimpleDateFormat("MM"); // 01
formatter = new SimpleDateFormat("MMM"); // Jan
formatter = new SimpleDateFormat("MMMM"); // January
// The day
formatter = new SimpleDateFormat("d"); // 9
formatter = new SimpleDateFormat("dd"); // 09
// The day in week
formatter = new SimpleDateFormat("E"); // Wed
formatter = new SimpleDateFormat("EEEE"); // Wednesday
// Get today's date
Date date = new Date();
// Some examples
formatter = new SimpleDateFormat("MM/dd/yy");
String s = formatter.format(date); // 01/09/02
formatter = new SimpleDateFormat("dd-MMM-yy");
s = formatter.format(date); // 29-Jan-02 //
Examples with date and time;
formatter = new SimpleDateFormat("yyyy.MM.dd.HH.mm.ss");
s = formatter.format(date);
formatter = new SimpleDateFormat("E, dd MMM yyyy HH:mm:ss Z");
s = formatter.format(date); // Tue, 09 Jan 2002 22:14:02 -0500
Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.