All Packages Class Hierarchy This Package Previous Next Index
java.lang.Object
|
+----java.text.Format
|
+----java.text.DateFormat
|
+----java.text.SimpleDateFormat
SimpleDateFormat is a concrete class for formatting and
parsing dates in a locale-sensitive manner. It allows for formatting
(millis -> text), parsing (text -> millis), 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:
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) '
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.
(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:
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, "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.
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.
SimpleDateFormat()
SimpleDateFormat(String)
SimpleDateFormat(String, DateFormatSymbols)
SimpleDateFormat(String, Locale)
applyLocalizedPattern(String)
applyPattern(String)
clone()
equals(Object)
format(Date, StringBuffer, FieldPosition)
Formats a date or time, which is the standard millis since 24:00 GMT, Jan 1, 1970.
getDateFormatSymbols()
hashCode()
parse(String, ParsePosition)
setDateFormatSymbols(DateFormatSymbols)
toLocalizedPattern()
toPattern()
SimpleDateFormat
public SimpleDateFormat()
SimpleDateFormat
public SimpleDateFormat(String pattern)
SimpleDateFormat
public SimpleDateFormat(String pattern,
Locale loc)
SimpleDateFormat
public SimpleDateFormat(String pattern,
DateFormatSymbols formatData)
format
public StringBuffer format(Date date,
StringBuffer toAppendTo,
FieldPosition pos)
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,
ParsePosition pos)
toPattern
public String toPattern()
toLocalizedPattern
public String toLocalizedPattern()
applyPattern
public void applyPattern(String pattern)
applyLocalizedPattern
public void applyLocalizedPattern(String pattern)
getDateFormatSymbols
public DateFormatSymbols getDateFormatSymbols()
setDateFormatSymbols
public void setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
clone
public Object clone()
hashCode
public int hashCode()
equals
public boolean equals(Object obj)
All Packages Class Hierarchy This Package Previous Next Index