Class SimpleDateFormat
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 getTimeInstance , getDateInstance , or getDateTimeInstance in 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 DateFormat .
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 ‘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’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 ‘A’ to ‘Z’ and from ‘a’ to ‘z’ are reserved):
Chart shows pattern letters, date/time component, presentation, and examples.
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
- 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.
- 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»), 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» 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.
If week year ‘Y’ is specified and the calendar doesn’t support any week years, the calendar year ( ‘y’ ) is used instead. The support of week years can be tested with a call to getCalendar() . isWeekDateSupported() .
- Letter M produces context-sensitive month names, such as the embedded form of names. Letter M is context-sensitive in the sense that when it is used in the standalone pattern, for example, «MMMM», it gives the standalone form of a month name and when it is used in the pattern containing other field(s), for example, «d MMMM», it gives the format form of a month name. For example, January in the Catalan language is «de gener» in the format form while it is «gener» in the standalone form. In this case, «MMMM» will produce «gener» and the month part of the «d MMMM» will produce «de gener». If a DateFormatSymbols has been set explicitly with constructor SimpleDateFormat(String,DateFormatSymbols) or method setDateFormatSymbols(DateFormatSymbols) , the month names given by the DateFormatSymbols are used.
- Letter L produces the standalone form of month names.
GMTOffsetTimeZone:GMTSign Hours:Minutes Sign: one of+ -Hours: Digit Digit Digit Minutes: Digit Digit Digit: one of0 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.
RFC822TimeZone: Sign TwoDigitHours Minutes TwoDigitHours: Digit Digit
ISO8601TimeZone: OneLetterISO8601TimeZone TwoLetterISO8601TimeZone ThreeLetterISO8601TimeZone OneLetterISO8601TimeZone: Sign TwoDigitHoursZTwoLetterISO8601TimeZone: Sign TwoDigitHours MinutesZThreeLetterISO8601TimeZone: Sign TwoDigitHours:MinutesZ
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.
Examples of date and time patterns interpreted in the U.S. locale
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 «yyyy-MM-dd’T’HH:mm:ss.SSSXXX» 2001-07-04T12:08:56.235-07:00 «YYYY-‘W’ww-u» 2001-W27-3
Synchronization
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.
Parsing and Formatting
The temporal-based classes in the Date-Time API provide parse methods for parsing a string that contains date and time information. These classes also provide format methods for formatting temporal-based objects for display. In both cases, the process is similar: you provide a pattern to the DateTimeFormatter to create a formatter object. This formatter is then passed to the parse or format method.
The DateTimeFormatter class provides numerous predefined formatters, or you can define your own.
The parse and the format methods throw an exception if a problem occurs during the conversion process. Therefore, your parse code should catch the DateTimeParseException error and your format code should catch the DateTimeException error. For more information on exception handing, see Catching and Handling Exceptions.
The DateTimeFormatter class is both immutable and thread-safe; it can (and should) be assigned to a static constant where appropriate.
Version Note: The java.time date-time objects can be used directly with java.util.Formatter and String.format by using the familiar pattern-based formatting that was used with the legacy java.util.Date and java.util.Calendar classes.
Parsing
The one-argument parse(CharSequence) method in the LocalDate class uses the ISO_LOCAL_DATE formatter. To specify a different formatter, you can use the two-argument parse(CharSequence, DateTimeFormatter) method. The following example uses the predefined BASIC_ISO_DATE formatter, which uses the format 19590709 for July 9, 1959.
String in = . ; LocalDate date = LocalDate.parse(in, DateTimeFormatter.BASIC_ISO_DATE);
You can also define a formatter using your own pattern. The following code, from the Parse example, creates a formatter that applies a format of «MMM d yyyy». This format specifies three characters to represent the month, one digit to represent day of the month, and four digits to represent the year. A formatter created using this pattern would recognize strings such as «Jan 3 2003» or «Mar 23 1994». However, to specify the format as «MMM dd yyyy», with two characters for day of the month, then you would have to always use two characters, padding with a zero for a one-digit date: «Jun 03 2003».
String input = . ; try < DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM d yyyy"); LocalDate date = LocalDate.parse(input, formatter); System.out.printf("%s%n", date); >catch (DateTimeParseException exc) < System.out.printf("%s is not parsable!%n", input); throw exc; // Rethrow the exception. >// 'date' has been successfully parsed The documentation for the DateTimeFormatter class specifies the full list of symbols that you can use to specify a pattern for formatting or parsing.
The StringConverter example on the Non-ISO Date Conversion page provides another example of a date formatter.
Formatting
The format(DateTimeFormatter) method converts a temporal-based object to a string representation using the specified format. The following code, from the Flight example, converts an instance of ZonedDateTime using the format «MMM d yyy hh:mm a». The date is defined in the same manner as was used for the previous parsing example, but this pattern also includes the hour, minutes, and a.m. and p.m. components.
ZoneId leavingZone = . ; ZonedDateTime departure = . ; try < DateTimeFormatter format = DateTimeFormatter.ofPattern("MMM d yyyy hh:mm a"); String out = departure.format(format); System.out.printf("LEAVING: %s (%s)%n", out, leavingZone); >catch (DateTimeException exc)
The output for this example, which prints both the arrival and departure time, is as follows:
LEAVING: Jul 20 2013 07:30 PM (America/Los_Angeles) ARRIVING: Jul 21 2013 10:20 PM (Asia/Tokyo)