Whole document tree
|
JavaTM 2 Platform Std. Ed. v1.3.1 |
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||
java.text
Class SimpleDateFormat
java.lang.Object | +--java.text.Format | +--java.text.DateFormat | +--java.text.SimpleDateFormat
- All Implemented Interfaces:
- Cloneable, Serializable
- 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
In the example, the time valueSimpleTimeZone 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 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 ("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 the year pattern has more than 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.
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, Serialized Form
| Fields inherited from class java.text.DateFormat |
AM_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 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,
DateFormatSymbols formatData)
Construct a SimpleDateFormat using the given pattern and locale-specific symbol data. |
|
SimpleDateFormat(String pattern,
Locale loc)
Construct a SimpleDateFormat using the given pattern and locale. |
|
| 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(Date date,
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. |
int |
hashCode()
Override hashCode. |
Date |
parse(String text,
ParsePosition pos)
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. |
String |
toLocalizedPattern()
Return a localized pattern string describing this date format. |
String |
toPattern()
Return a pattern string describing this date format. |
| Methods inherited from class java.text.DateFormat |
format, format, getAvailableLocales, getCalendar, getDateInstance, getDateInstance, getDateInstance, getDateTimeInstance, getDateTimeInstance, getDateTimeInstance, getInstance, getNumberFormat, getTimeInstance, getTimeInstance, getTimeInstance, getTimeZone, isLenient, parse, parseObject, setCalendar, setLenient, setNumberFormat, setTimeZone |
| Methods inherited from class java.text.Format |
format, parseObject |
| Methods inherited from class java.lang.Object |
finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
SimpleDateFormat
public SimpleDateFormat()
- Construct a SimpleDateFormat using the default pattern for the default
locale. Note: Not all locales support SimpleDateFormat; for full
generality, use the factory methods in the DateFormat class.
- See Also:
DateFormat
SimpleDateFormat
public SimpleDateFormat(String pattern)
- Construct a SimpleDateFormat using the given pattern in the default locale. Note: Not all locales support SimpleDateFormat; for full generality, use the factory methods in the DateFormat class.
SimpleDateFormat
public SimpleDateFormat(String pattern, Locale loc)
- Construct a SimpleDateFormat using the given pattern and locale. Note: Not all locales support SimpleDateFormat; for full generality, use the factory methods in the DateFormat class.
SimpleDateFormat
public SimpleDateFormat(String pattern, DateFormatSymbols formatData)
- Construct a SimpleDateFormat using the given pattern and locale-specific symbol data.
| Method Detail |
set2DigitYearStart
public 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.
- Parameters:
startDate- During parsing, two digit years will be placed in the rangestartDatetostartDate + 100 years.
get2DigitYearStart
public Date get2DigitYearStart()
- Returns the beginning date of the 100-year period 2-digit years are interpreted
as being within.
- Returns:
- the start of the 100-year period into which two digit years are parsed
format
public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition pos)
- Overrides DateFormat
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
- Overrides:
formatin classDateFormat
- Parameters:
date- 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.- Returns:
- the formatted date-time string.
- See Also:
DateFormat
parse
public Date parse(String text, ParsePosition pos)
- Overrides DateFormat
- Overrides:
parsein classDateFormat
- See Also:
DateFormat
toPattern
public String toPattern()
- Return a pattern string describing this date format.
toLocalizedPattern
public String toLocalizedPattern()
- Return a localized pattern string describing this date format.
applyPattern
public void applyPattern(String pattern)
- Apply the given unlocalized pattern string to this date format.
applyLocalizedPattern
public void applyLocalizedPattern(String pattern)
- Apply the given localized pattern string to this date format.
getDateFormatSymbols
public DateFormatSymbols getDateFormatSymbols()
- Gets the date/time formatting data.
- Returns:
- a copy of the date-time formatting data associated with this date-time formatter.
setDateFormatSymbols
public void setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
- Allows you to set the date/time formatting data.
- Parameters:
newFormatData- the given date-time formatting data.
clone
public Object clone()
- Overrides Cloneable
- Overrides:
clonein classDateFormat
- Following copied from class:
java.lang.Object- Returns:
- a clone of this instance.
- Throws:
CloneNotSupportedException- if the object's class does not support theCloneableinterface. Subclasses that override theclonemethod can also throw this exception to indicate that an instance cannot be cloned.OutOfMemoryError- if there is not enough memory.- See Also:
Cloneable
hashCode
public int hashCode()
- Override hashCode.
Generates the hash code for the SimpleDateFormat object
- Overrides:
hashCodein classDateFormat
- Following copied from class:
java.lang.Object- Returns:
- a hash code value for this object.
- See Also:
Object.equals(java.lang.Object),Hashtable
equals
public boolean equals(Object obj)
- Override equals.
- Overrides:
equalsin classDateFormat
- Following copied from class:
java.lang.Object- Parameters:
obj- the reference object with which to compare.- Returns:
trueif this object is the same as the obj argument;falseotherwise.- See Also:
Boolean.hashCode(),Hashtable
|
JavaTM 2 Platform Std. Ed. v1.3.1 |
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
| SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||
Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Java, Java 2D, and JDBC are trademarks or registered trademarks of Sun Microsystems, Inc. in the US and other countries.
Copyright 1993-2001 Sun Microsystems, Inc. 901 San Antonio Road
Palo Alto, California, 94303, U.S.A. All Rights Reserved.