com.ibm.icu.text
public class SimpleDateFormat extends DateFormat
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.
Time Format Syntax:
To specify the time format use a time pattern string. In this pattern, all ASCII letters are reserved as pattern letters, which are defined as the following:
* These items are not supported by Java's SimpleDateFormat.Symbol Meaning Presentation Example ------ ------- ------------ ------- G era designator (Text) AD y† year (Number) 1996 Y* year (week of year) (Number) 1997 u* extended year (Number) 4601 M month in year (Text & Number) July & 07 d day in month (Number) 10 h hour in am/pm (1~12) (Number) 12 H hour in day (0~23) (Number) 0 m minute in hour (Number) 30 s second in minute (Number) 55 S fractional second (Number) 978 E day of week (Text) Tuesday e* day of week (local 1~7) (Number) 2 D day in year (Number) 189 F day of week in month (Number) 2 (2nd Wed in July) w week in year (Number) 27 W week in month (Number) 2 a am/pm marker (Text) PM k hour in day (1~24) (Number) 24 K hour in am/pm (0~11) (Number) 0 z time zone (Text) Pacific Standard Time Z time zone (RFC 822) (Number) -0800 v time zone (generic) (Text) Pacific Time g* Julian day (Number) 2451334 A* milliseconds in day (Number) 69540000 ' escape for text (Delimiter) 'Date=' '' single quote (Literal) 'o''clock'
The count of pattern letters determine the format.
(Text): 4 or more pattern letters--use full form, < 4--use short or abbreviated form if one exists.
(Number): the minimum number of digits. Shorter numbers are zero-padded to this amount. Year is handled specially; that is, if the count of 'y' is 2, the Year will be truncated to 2 digits. (e.g., if "yyyy" produces "1997", "yy" produces "97".) Unlike other fields, fractional seconds are padded on the right with zero.
(Text & Number): 3 or over, use text, otherwise use number.
Any characters in the pattern that are not in the ranges of ['a'..'z'] and ['A'..'Z'] will be treated as quoted text. For instance, characters like ':', '.', ' ', '#' and '@' will appear in the resulting time text even they are not embraced within single quotes.
A pattern containing any invalid pattern letter will result in a thrown exception during formatting or parsing.
Examples Using the US Locale:
Code Sample:Format Pattern Result -------------- ------- "yyyy.MM.dd G 'at' HH:mm:ss vvvv" ->> 1996.07.10 AD at 15:08:56 Pacific Time "EEE, MMM d, ''yy" ->> Wed, July 10, '96 "h:mm a" ->> 12:08 PM "hh 'o''clock' a, zzzz" ->> 12 o'clock PM, Pacific Daylight Time "K:mm a, vvv" ->> 0:00 PM, PT "yyyyy.MMMMM.dd GGG hh:mm aaa" ->> 01996.July.10 AD 12:08 PM
In the example, the time valueSimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, "PST"); pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2*60*60*1000); pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2*60*60*1000);
// Format the current time. SimpleDateFormat formatter = new SimpleDateFormat ("yyyy.MM.dd G 'at' hh:mm:ss a zzz"); Date currentTime_1 = new Date(); String dateString = formatter.format(currentTime_1);
// Parse the previous string back into a Date. ParsePosition pos = new ParsePosition(0); Date currentTime_2 = formatter.parse(dateString, pos);
currentTime_2
obtained from
parsing will be equal to currentTime_1
. However, they may not be
equal if the am/pm marker 'a' is left out from the format pattern while
the "hour in am/pm" pattern symbol is used. This information loss can
happen when formatting the time in PM.
When parsing a date string using the abbreviated year pattern ("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 java.lang.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 the year pattern does not have exactly two 'y' characters, 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.
When numeric fields abut one another directly, with no intervening delimiter characters, they constitute a run of abutting numeric fields. Such runs are parsed specially. For example, the format "HHmmss" parses the input text "123456" to 12:34:56, parses the input text "12345" to 1:23:45, and fails to parse "1234". In other words, the leftmost field of the run is flexible, while the others keep a fixed width. If the parse fails anywhere in the run, then the leftmost field is shortened by one character, and the entire run is parsed again. This is repeated until either the parse succeeds or the leftmost field is one character in length. If the parse still fails at that point, the parse of the run fails.
For time zones that have no names, use strings GMT+hours:minutes or GMT-hours:minutes.
The calendar defines what is the first day of the week, the first week of the year, whether hours are zero based or not (0 vs 12 or 24), and the time zone. There is one common decimal format to handle all the numbers; the digit count is handled programmatically according to the pattern.
See Also: Calendar GregorianCalendar TimeZone DateFormat DateFormatSymbols DecimalFormat
UNKNOWN: ICU 2.0
Constructor Summary | |
---|---|
SimpleDateFormat()
Construct a SimpleDateFormat using the default pattern for the default
locale. | |
SimpleDateFormat(String pattern)
Construct a SimpleDateFormat using the given pattern in the default
locale. | |
SimpleDateFormat(String pattern, Locale loc)
Construct a SimpleDateFormat using the given pattern and locale.
| |
SimpleDateFormat(String pattern, ULocale loc)
Construct a SimpleDateFormat using the given pattern and locale.
| |
SimpleDateFormat(String pattern, DateFormatSymbols formatData)
Construct a SimpleDateFormat using the given pattern and
locale-specific symbol data.
| |
SimpleDateFormat(String pattern, DateFormatSymbols formatData, ULocale loc) |
Method Summary | |
---|---|
void | applyLocalizedPattern(String pattern)
Apply the given localized pattern string to this date format. |
void | applyPattern(String pattern)
Apply the given unlocalized pattern string to this date format. |
Object | clone()
Overrides Cloneable |
boolean | equals(Object obj)
Override equals. |
StringBuffer | format(Calendar cal, StringBuffer toAppendTo, FieldPosition pos)
Overrides DateFormat.
|
Date | get2DigitYearStart()
Returns the beginning date of the 100-year period 2-digit years are interpreted
as being within. |
DateFormatSymbols | getDateFormatSymbols()
Gets the date/time formatting data. |
static SimpleDateFormat | getInstance(Calendar.FormatConfiguration formatConfig) |
protected DateFormatSymbols | getSymbols()
Method for subclasses to access the DateFormatSymbols. |
int | hashCode()
Override hashCode.
|
protected int | matchQuarterString(String text, int start, int field, String[] data, Calendar cal)
Attempt to match the text at a given position against an array of quarter
strings. |
protected int | matchString(String text, int start, int field, String[] data, Calendar cal)
Attempt to match the text at a given position against an array of
strings. |
void | parse(String text, Calendar cal, ParsePosition parsePos)
Overrides DateFormat |
void | set2DigitYearStart(Date startDate)
Sets the 100-year period 2-digit years will be interpreted as being in
to begin on the date the user specifies. |
void | setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
Allows you to set the date/time formatting data. |
void | setNumberFormat(NumberFormat newNumberFormat)
Overrides superclass method |
protected String | subFormat(char ch, int count, int beginOffset, FieldPosition pos, DateFormatSymbols formatData, Calendar cal)
Format a single field, given its pattern character. |
protected void | subFormat(StringBuffer buf, char ch, int count, int beginOffset, FieldPosition pos, Calendar cal)
Format a single field; useFastFormat variant. |
protected int | subParse(String text, int start, char ch, int count, boolean obeyCount, boolean allowNegative, boolean[] ambiguousYear, Calendar cal)
Protected method that converts one field of the input string into a
numeric field value in cal . |
String | toLocalizedPattern()
Return a localized pattern string describing this date format. |
String | toPattern()
Return a pattern string describing this date format. |
protected void | zeroPaddingNumber(StringBuffer buf, int value, int minDigits, int maxDigits)
Internal high-speed method. |
protected String | zeroPaddingNumber(long value, int minDigits, int maxDigits)
Formats a number with the specified minimum and maximum number of digits. |
See Also: DateFormat
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
UNKNOWN: ICU 2.0
Deprecated: This API is ICU internal only.
UNKNOWN: ICU 3.2
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Formats a date or time, which is the standard millis since January 1, 1970, 00:00:00 GMT.
Example: using the US locale: "yyyy.MM.dd G 'at' HH:mm:ss zzz" ->> 1996.07.10 AD at 15:08:56 PDT
Parameters: cal the calendar whose date-time value is to be formatted into a date-time string toAppendTo where the new date-time text is to be appended pos the formatting position. On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns: the formatted date-time string.
See Also: DateFormat
UNKNOWN: ICU 2.0
Returns: the start of the 100-year period into which two digit years are parsed
UNKNOWN: ICU 2.0
Returns: a copy of the date-time formatting data associated with this date-time formatter.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
cal
is set to the index
of the best match, if there is one.Parameters: text the time text being parsed. start where to start parsing. field the date field being parsed. data the string array to parsed.
Returns: the new start position if matching succeeded; a negative
number indicating matching failure, otherwise. As a side effect,
sets the cal
field field
to the index
of the best match, if matching succeeded.
UNKNOWN: ICU 2.0
cal
is set to the index
of the best match, if there is one.Parameters: text the time text being parsed. start where to start parsing. field the date field being parsed. data the string array to parsed.
Returns: the new start position if matching succeeded; a negative
number indicating matching failure, otherwise. As a side effect,
sets the cal
field field
to the index
of the best match, if matching succeeded.
UNKNOWN: ICU 2.0
See Also: DateFormat
UNKNOWN: ICU 2.0
Parameters: startDate During parsing, two digit years will be placed in the range
startDate
to startDate + 100 years
.
UNKNOWN: ICU 2.0
Parameters: newFormatSymbols the new symbols
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Parameters: ch the pattern character count the number of times ch is repeated in the pattern beginOffset the offset of the output string at the start of this field; used to set pos when appropriate pos receives the position of a field, when appropriate formatData the symbols for this formatter
UNKNOWN: ICU 2.0
Deprecated: This API is ICU internal only.
Format a single field; useFastFormat variant. Reuses a StringBuffer for results instead of creating a String on the heap for each call. NOTE We don't really need the beginOffset parameter, EXCEPT for the need to support the slow subFormat variant (above) which has to pass it in to us. TODO make this API publicUNKNOWN:
cal
. Returns -start (for
ParsePosition) if failed. Subclasses may override this method to
modify or add parsing capabilities.Parameters: text the time text to be parsed. start where to start parsing. ch the pattern character for the date field text to be parsed. count the count of a pattern character. obeyCount if true, then the next field directly abuts this one, and we should use the count to know when to stop parsing. ambiguousYear return parameter; upon return, if ambiguousYear[0] is true, then a two-digit year was parsed and may need to be readjusted.
Returns: the new start position if matching succeeded; a negative
number indicating matching failure, otherwise. As a side effect,
set the appropriate field of cal
with the parsed
value.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Deprecated: This API is ICU internal only.
Internal high-speed method. Reuses a StringBuffer for results instead of creating a String on the heap for each call.UNKNOWN:
UNKNOWN: ICU 2.0