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
.
Date and time formats are specified by date and time pattern strings. Within date and time pattern strings, unquoted letters from 'A'
to 'Z'
and from 'a'
to 'z'
are interpreted as pattern letters representing the components of a date or time string. Text can be quoted using single quotes ('
) to avoid interpretation. "''"
represents a single quote. All other characters are not interpreted; they're simply copied into the output string during formatting or matched against the input string during parsing.
The following pattern letters are defined (all other characters from 'A'
to 'Z'
and from 'a'
to 'z'
are reserved):
Letter | Date or Time Component | Presentation | Examples |
---|---|---|---|
G |
Era designator | Text |
AD |
y |
Year | Year |
1996 ; 96 |
Y |
Week year | Year |
2009 ; 09 |
M |
Month in year (context sensitive) | Month |
July ; Jul ; 07 |
L |
Month in year (standalone form) | Month |
July ; Jul ; 07 |
w |
Week in year | Number |
27 |
W |
Week in month | Number |
2 |
D |
Day in year | Number |
189 |
d |
Day in month | Number |
10 |
F |
Day of week in month | Number |
2 |
E |
Day name in week | Text |
Tuesday ; Tue |
u |
Day number of week (1 = Monday, ..., 7 = Sunday) | Number |
1 |
a |
Am/pm marker | Text |
PM |
H |
Hour in day (0-23) | Number |
0 |
k |
Hour in day (1-24) | Number |
24 |
K |
Hour in am/pm (0-11) | Number |
0 |
h |
Hour in am/pm (1-12) | Number |
12 |
m |
Minute in hour | Number |
30 |
s |
Second in minute | Number |
55 |
S |
Millisecond | Number |
978 |
z |
Time zone | General time zone |
Pacific Standard Time ; PST ; GMT-08:00 |
Z |
Time zone | RFC 822 time zone |
-0800 |
X |
Time zone | ISO 8601 time zone |
-08 ; -0800 ; -08:00 |
Calendar
is the Gregorian calendar, the following rules are applied.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. 'Y'
is specified and the calendar doesn't support any week years, the calendar year ('y'
) is used instead. The support of week years can be tested with a call to getCalendar()
.isWeekDateSupported()
.DateFormatSymbols
has been set explicitly with constructor SimpleDateFormat(String,
DateFormatSymbols)
or method setDateFormatSymbols(DateFormatSymbols)
, the month names given by the DateFormatSymbols
are used.GMTOffsetTimeZone: GMT Sign Hours : Minutes Sign: one of + - Hours: Digit Digit Digit Minutes: Digit Digit Digit: one of 0 1 2 3 4 5 6 7 8 9Hours must be between 0 and 23, and Minutes must be between 00 and 59. The format is locale independent and digits must be taken from the Basic Latin block of the Unicode standard.
For parsing, RFC 822 time zones are also accepted.
RFC822TimeZone: Sign TwoDigitHours Minutes TwoDigitHours: Digit DigitTwoDigitHours must be between 00 and 23. Other definitions are as for general time zones.
For parsing, general time zones are also accepted.
ISO8601TimeZone: OneLetterISO8601TimeZone TwoLetterISO8601TimeZone ThreeLetterISO8601TimeZone OneLetterISO8601TimeZone: Sign TwoDigitHours Z TwoLetterISO8601TimeZone: Sign TwoDigitHours Minutes Z ThreeLetterISO8601TimeZone: Sign TwoDigitHours : Minutes ZOther definitions are as for general time zones or RFC 822 time zones.
For formatting, if the offset value from GMT is 0, "Z"
is produced. If the number of pattern letters is 1, any fraction of an hour is ignored. For example, if the pattern is "X"
and the time zone is "GMT+05:30"
, "+05"
is produced.
For parsing, "Z"
is parsed as the UTC time zone designator. General time zones are not accepted.
If the number of pattern letters is 4 or more, IllegalArgumentException
is thrown when constructing a SimpleDateFormat
or applying a pattern.
SimpleDateFormat
also supports localized date and time pattern strings. In these strings, the pattern letters described above may be replaced with other, locale dependent, pattern letters. SimpleDateFormat
does not deal with the localization of text other than the pattern letters; that's up to the client of the class. Date and Time Pattern | Result |
---|---|
"yyyy.MM.dd G 'at' HH:mm:ss z" |
2001.07.04 AD at 12:08:56 PDT |
"EEE, MMM d, ''yy" |
Wed, Jul 4, '01 |
"h:mm a" |
12:08 PM |
"hh 'o''clock' a, zzzz" |
12 o'clock PM, Pacific Daylight Time |
"K:mm a, z" |
0:08 PM, PDT |
"yyyyy.MMMMM.dd GGG hh:mm aaa" |
02001.July.04 AD 12:08 PM |
"EEE, d MMM yyyy HH:mm:ss Z" |
Wed, 4 Jul 2001 12:08:56 -0700 |
"yyMMddHHmmssZ" |
010704120856-0700 |
"yyyy-MM-dd'T'HH:mm:ss.SSSZ" |
2001-07-04T12:08:56.235-0700 |
"yyyy-MM-dd'T'HH:mm:ss.SSSXXX" |
2001-07-04T12:08:56.235-07:00 |
"YYYY-'W'ww-u" |
2001-W27-3 |
Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.
Calendar
, TimeZone
, DateFormat
, DateFormatSymbols
, Serialized FormDateFormat.Field
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
public SimpleDateFormat()
Constructs a SimpleDateFormat
using the default pattern and date format symbols for the default FORMAT
locale. Note: This constructor may not support all locales. For full coverage, use the factory methods in the DateFormat
class.
public SimpleDateFormat(String pattern)
Constructs a SimpleDateFormat
using the given pattern and the default date format symbols for the default FORMAT
locale. Note: This constructor may not support all locales. For full coverage, use the factory methods in the DateFormat
class.
This is equivalent to calling SimpleDateFormat(pattern, Locale.getDefault(Locale.Category.FORMAT))
.
pattern
- the pattern describing the date and time formatNullPointerException
- if the given pattern is nullIllegalArgumentException
- if the given pattern is invalidLocale.getDefault(java.util.Locale.Category)
, Locale.Category.FORMAT
public SimpleDateFormat(String pattern, Locale locale)
Constructs a SimpleDateFormat
using the given pattern and the default date format symbols for the given locale. Note: This constructor may not support all locales. For full coverage, use the factory methods in the DateFormat
class.
pattern
- the pattern describing the date and time formatlocale
- the locale whose date format symbols should be usedNullPointerException
- if the given pattern or locale is nullIllegalArgumentException
- if the given pattern is invalidpublic SimpleDateFormat(String pattern, DateFormatSymbols formatSymbols)
Constructs a SimpleDateFormat
using the given pattern and date format symbols.
pattern
- the pattern describing the date and time formatformatSymbols
- the date format symbols to be used for formattingNullPointerException
- if the given pattern or formatSymbols is nullIllegalArgumentException
- if the given pattern is invalidpublic 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.
startDate
- During parsing, two digit years will be placed in the range startDate
to startDate + 100 years
.get2DigitYearStart()
public Date get2DigitYearStart()
Returns the beginning date of the 100-year period 2-digit years are interpreted as being within.
set2DigitYearStart(java.util.Date)
public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition pos)
Formats the given Date
into a date/time string and appends the result to the given StringBuffer
.
format
in class DateFormat
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.NullPointerException
- if the given date
is null
.public AttributedCharacterIterator formatToCharacterIterator(Object obj)
Formats an Object producing an AttributedCharacterIterator
. You can use the returned AttributedCharacterIterator
to build the resulting String, as well as to determine information about the resulting String.
Each attribute key of the AttributedCharacterIterator will be of type DateFormat.Field
, with the corresponding attribute value being the same as the attribute key.
formatToCharacterIterator
in class Format
obj
- The object to formatNullPointerException
- if obj is null.IllegalArgumentException
- if the Format cannot format the given object, or if the Format's pattern string is invalid.public Date parse(String text, ParsePosition pos)
Parses text from a string to produce a Date
.
The method attempts to parse text starting at the index given by pos
. If parsing succeeds, then the index of pos
is updated to the index after the last character used (parsing does not necessarily use all characters up to the end of the string), and the parsed date is returned. The updated pos
can be used to indicate the starting point for the next call to this method. If an error occurs, then the index of pos
is not changed, the error index of pos
is set to the index of the character where the error occurred, and null is returned.
This parsing operation uses the calendar
to produce a Date
. All of the calendar
's date-time fields are cleared before parsing, and the calendar
's default values of the date-time fields are used for any missing date-time information. For example, the year value of the parsed Date
is 1970 with GregorianCalendar
if no year value is given from the parsing operation. The TimeZone
value may be overwritten, depending on the given pattern and the time zone value in text
. Any TimeZone
value that has previously been set by a call to setTimeZone
may need to be restored for further operations.
parse
in class DateFormat
text
- A String
, part of which should be parsed.pos
- A ParsePosition
object with index and error index information as described above.Date
parsed from the string. In case of error, returns null.NullPointerException
- if text
or pos
is null.public String toPattern()
Returns a pattern string describing this date format.
public String toLocalizedPattern()
Returns a localized pattern string describing this date format.
public void applyPattern(String pattern)
Applies the given pattern string to this date format.
pattern
- the new date and time pattern for this date formatNullPointerException
- if the given pattern is nullIllegalArgumentException
- if the given pattern is invalidpublic void applyLocalizedPattern(String pattern)
Applies the given localized pattern string to this date format.
pattern
- a String to be mapped to the new date and time format pattern for this formatNullPointerException
- if the given pattern is nullIllegalArgumentException
- if the given pattern is invalidpublic DateFormatSymbols getDateFormatSymbols()
Gets a copy of the date and time format symbols of this date format.
setDateFormatSymbols(java.text.DateFormatSymbols)
public void setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
Sets the date and time format symbols of this date format.
newFormatSymbols
- the new date and time format symbolsNullPointerException
- if the given newFormatSymbols is nullgetDateFormatSymbols()
public Object clone()
Creates a copy of this SimpleDateFormat
. This also clones the format's date format symbols.
clone
in class DateFormat
SimpleDateFormat
Cloneable
public int hashCode()
Returns the hash code value for this SimpleDateFormat
object.
hashCode
in class DateFormat
SimpleDateFormat
object.Object.equals(java.lang.Object)
, System.identityHashCode(java.lang.Object)
public boolean equals(Object obj)
Compares the given object with this SimpleDateFormat
for equality.
equals
in class DateFormat
obj
- the reference object with which to compare.SimpleDateFormat
Object.hashCode()
, HashMap
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