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java.lang.Object
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+----java.text.Format
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+----java.text.DateFormat
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+----java.text.SimpleDateFormat
SimpleDateFormat allows clients to start with choosing any user-defined patterns for date-time formatting. However, clients are encouraged to create a date-time formatter through using getTimeFormat, getDateFormat, or getDateTimeFormat method in DateFormat. Each of these methods can return a date/time formatter initialized with a default format pattern. Clients may modify the format pattern using the setPattern function as so desired. For more information on using these functions, see DateFormat.
Time format syntax:
The time format is specified by means of a string time pattern. In this pattern, all ASCII letters are reserved as pattern letters, which are defined as the following:
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 '' single quote 'The count of pattern letters determine the format.
(Text): 4 or more, use full form, <4, use short or abbreviated form if 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 an exception to be thrown during formatting or parsing.
Examples using the US locale:
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
Code Sample:
SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000);
pdt.setStartRule(DateFields.APRIL, 1, DateFields.SUNDAY, 2*60*60*1000);
pdt.setEndRule(DateFields.OCTOBER, -1, DateFields.SUNDAY, 2*60*60*1000);
Calendar calendar = new GregorianCalendar(pdt);
// 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.
ParseStatus status = new ParseStatus();
Date currentTime_2 = formatter.parse(dateString, status);
In the above 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.
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 timezone. There is one common decimal format to handle all the numbers; the digit count is handled programmatically according to the pattern.
SimpleDateFormat(String)
SimpleDateFormat(String, DateFormatData)
clone()
equals(Object)
format(Date, StringBuffer, FormatStatus)
Formats a date or time, which is the standard millis since 24:00 GMT, Jan 1, 1970.
getDateFormatData()
getPattern(boolean)
hashCode()
parse(String, ParseStatus)
setDateFormatData(DateFormatData)
setPattern(String, boolean)
SimpleDateFormat
public SimpleDateFormat(String newPattern)
SimpleDateFormat
public SimpleDateFormat(String newPattern,
DateFormatData newFormatData)
format
public StringBuffer format(Date date,
StringBuffer toAppendTo,
FormatStatus status)
Formats a date or time, which is the standard millis since 24:00 GMT, Jan 1, 1970.
Example: using the US locale: "yyyy.MM.dd e 'at' HH:mm:ss zzz" ->> 1996.07.10 AD at 15:08:56 PDT
parse
public Date parse(String text,
ParseStatus status)
getPattern
public String getPattern(boolean localized)
setPattern
public void setPattern(String newPattern,
boolean localized)
getDateFormatData
public DateFormatData getDateFormatData() throws InternalError
setDateFormatData
public void setDateFormatData(DateFormatData newFormatData) throws InternalError
clone
public Object clone()
hashCode
public synchronized int hashCode()
equals
public boolean equals(Object obj)
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