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:
The count of pattern letters determine the format.Symbol Meaning Presentation Example ------ ------- ------------ ------- G era designator (Text) AD y year (Number) 1996 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 millisecond (Number) 978 E day in week (Text) Tuesday 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 ' escape for text (Delimiter) '' single quote (Literal) '
(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.
(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 z" 1996.07.10 AD at 15:08:56 PDT "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, z" 0:00 PM, PST "yyyyy.MMMMM.dd GGG hh:mm aaa" 1996.July.10 AD 12:08 PM
SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, "PST");
pdt.setStartRule(DateFields.APRIL, 1, DateFields.SUNDAY, 2*60*60*1000);
pdt.setEndRule(DateFields.OCTOBER, -1, DateFields.SUNDAY, 2*60*60*1000);
// Format the current time.
SimpleDateFormat formatter
= new SimpleDateFormat ("yyyy.mm.dd e '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);
In the example, the time value 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,
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.
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.
Calendar,
GregorianCalendar,
TimeZone,
DateFormat,
DateFormatSymbols,
DecimalFormatAM_PM_FIELD, calendar, DATE_FIELD, DAY_OF_WEEK_FIELD, DAY_OF_WEEK_IN_MONTH_FIELD, DAY_OF_YEAR_FIELD, DEFAULT, ERA_FIELD, FULL, HOUR_OF_DAY0_FIELD, HOUR_OF_DAY1_FIELD, HOUR0_FIELD, HOUR1_FIELD, LONG, MEDIUM, MILLISECOND_FIELD, MINUTE_FIELD, MONTH_FIELD, numberFormat, SECOND_FIELD, SHORT, TIMEZONE_FIELD, WEEK_OF_MONTH_FIELD, WEEK_OF_YEAR_FIELD, YEAR_FIELD| Constructor and Description |
|---|
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,
DateFormatSymbols formatData)
Constructs a SimpleDateFormat using the given pattern and date format symbols.
|
SimpleDateFormat(String pattern,
Locale loc)
Construct a SimpleDateFormat using the given pattern and locale.
|
| Modifier and Type | Method and Description |
|---|---|
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)
Overrides equals
|
StringBuffer |
format(Date date,
StringBuffer toAppendTo,
FieldPosition pos)
Overrides DateFormat
|
DateFormatSymbols |
getDateFormatSymbols()
Gets the date/time formatting data.
|
int |
hashCode()
Overrides hashCode
|
Date |
parse(String text,
ParsePosition pos)
Overrides DateFormat.
|
void |
setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
Allows you to set the date/time formatting data.
|
String |
toLocalizedPattern() |
String |
toPattern() |
format, format, getAvailableLocales, getCalendar, getDateInstance, getDateInstance, getDateInstance, getDateTimeInstance, getDateTimeInstance, getDateTimeInstance, getInstance, getNumberFormat, getTimeInstance, getTimeInstance, getTimeInstance, getTimeZone, isLenient, parse, parseObject, setCalendar, setLenient, setNumberFormat, setTimeZoneformat, parseObjectpublic SimpleDateFormat()
DateFormatpublic SimpleDateFormat(String pattern)
pattern - date formatpublic SimpleDateFormat(String pattern, Locale loc)
pattern - ?loc - ?public SimpleDateFormat(String pattern, DateFormatSymbols formatData)
pattern - the pattern describing the date and time formatformatData - the date format symbols to be used for formattingpublic StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition pos)
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 e 'at' HH:mm:ss zzz" ->> 1996.07.10 AD at 15:08:56 PDT
format in class DateFormatdate - the date-time value 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.DateFormatpublic Date parse(String text, ParsePosition pos)
parse in class DateFormattext - The date/time string to be parsedpos - On input, the position at which to start parsing; on
output, the position at which parsing terminated, or the
start position if the parse failed.DateFormat.setLenient(boolean)public String toPattern()
public String toLocalizedPattern()
public void applyPattern(String pattern)
pattern - patternpublic void applyLocalizedPattern(String pattern)
pattern - patternpublic DateFormatSymbols getDateFormatSymbols()
public void setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
newFormatSymbols - the given date-time formatting data.public Object clone()
DateFormatclone in class DateFormatCloneablepublic int hashCode()
DateFormathashCode in class DateFormatObject.equals(java.lang.Object),
Hashtablepublic boolean equals(Object obj)
DateFormatequals in class DateFormatobj - the reference object with which to compare.true if this object is the same as the obj
argument; false otherwise.Boolean.hashCode(),
Hashtable