Factory that creates instances of DateTimeFormatter from patterns and styles.
Datetime formatting is performed by the
DateTimeFormatter
class.
Three classes provide factory methods to create formatters, and this is one.
The others are
ISODateTimeFormat
and
DateTimeFormatterBuilder
.
This class provides two types of factory:
Pattern
provides a DateTimeFormatter based on
a pattern string that is mostly compatible with the JDK date patterns.
Style
provides a DateTimeFormatter based on a
two character style, representing short, medium, long and full.
For example, to use a patterm:
DateTime dt = new DateTime();
DateTimeFormatter fmt = DateTimeFormat.forPattern("MMMM, yyyy");
String str = fmt.print(dt);
The pattern syntax is mostly compatible with java.text.SimpleDateFormat -
time zone names cannot be parsed and a few more symbols are supported.
All ASCII letters are reserved as pattern letters, which are defined as follows:
Symbol Meaning Presentation Examples
------ ------- ------------ -------
G era text AD
C century of era (>=0) number 20
Y year of era (>=0) year 1996
x weekyear year 1996
w week of weekyear number 27
e day of week number 2
E day of week text Tuesday; Tue
y year year 1996
D day of year number 189
M month of year month July; Jul; 07
d day of month number 10
a halfday of day text PM
K hour of halfday (0~11) number 0
h clockhour of halfday (1~12) number 12
H hour of day (0~23) number 0
k clockhour of day (1~24) number 24
m minute of hour number 30
s second of minute number 55
S fraction of second number 978
z time zone text Pacific Standard Time; PST
Z time zone offset/id zone -0800; -08:00; America/Los_Angeles
' escape for text delimiter
'' single quote literal '
The count of pattern letters determine the format.
Text: If the number of pattern letters is 4 or more,
the full form is used; otherwise a short or abbreviated form is used if
available.
Number: The minimum number of digits. Shorter numbers
are zero-padded to this amount.
Year: Numeric presentation for year and weekyear fields
are handled specially. For example, if the count of 'y' is 2, the year
will be displayed as the zero-based year of the century, which is two
digits.
Month: 3 or over, use text, otherwise use number.
Zone: 'Z' outputs offset without a colon, 'ZZ' outputs
the offset with a colon, 'ZZZ' or more outputs the zone id.
Zone names: Time zone names ('z') cannot be parsed.
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.
DateTimeFormat is thread-safe and immutable, and the formatters it returns
are as well.
forPattern
public static DateTimeFormatter forPattern(String pattern)
Factory to create a formatter from a pattern string.
The pattern string is described above in the class level javadoc.
It is very similar to SimpleDateFormat patterns.
The format may contain locale specific output, and this will change as
you change the locale of the formatter.
Call
DateTimeFormatter.withLocale(Locale)
to switch the locale.
For example:
DateTimeFormat.forPattern(pattern).withLocale(Locale.FRANCE).print(dt);
pattern
- pattern specification
forStyle
public static DateTimeFormatter forStyle(String style)
Factory to create a format from a two character style pattern.
The first character is the date style, and the second character is the
time style. Specify a character of 'S' for short style, 'M' for medium,
'L' for long, and 'F' for full.
A date or time may be ommitted by specifying a style character '-'.
The returned formatter will dynamically adjust to the locale that
the print/parse takes place in. Thus you just call
DateTimeFormatter.withLocale(Locale)
and the Short/Medium/Long/Full
style for that locale will be output. For example:
DateTimeFormat.forStyle(style).withLocale(Locale.FRANCE).print(dt);
style
- two characters from the set {"S", "M", "L", "F", "-"}
patternForStyle
public static String patternForStyle(String style,
Locale locale)
Returns the pattern used by a particular style and locale.
The first character is the date style, and the second character is the
time style. Specify a character of 'S' for short style, 'M' for medium,
'L' for long, and 'F' for full.
A date or time may be ommitted by specifying a style character '-'.
style
- two characters from the set {"S", "M", "L", "F", "-"}locale
- locale to use, null means default