Class SimpleDateFormat
- java.lang.Object
-
- java.text.Format
-
- java.text.DateFormat
-
- java.text.SimpleDateFormat
- All Implemented Interfaces:
-
Serializable
,Cloneable
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 Patterns
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 |
-
Text: For formatting, 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. For parsing, both forms are accepted, independent of the number of pattern letters.
-
Number: For formatting, the number of pattern letters is the minimum number of digits, and shorter numbers are zero-padded to this amount. For parsing, the number of pattern letters is ignored unless it's needed to separate two adjacent fields.
-
Year: If the formatter's
Calendar
is the Gregorian calendar, the following rules are applied.
- For formatting, if the number of pattern letters is 2, the year is truncated to 2 digits; otherwise it is interpreted as a number.
- For parsing, if the number of pattern letters is more than 2, 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 parsing with 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 theSimpleDateFormat
instance is created. For example, using a pattern of "MM/dd/yy" and aSimpleDateFormat
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 byCharacter.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 week year'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 togetCalendar()
.isWeekDateSupported()
.
-
Month: If the number of pattern letters is 3 or more, the month is interpreted as text; otherwise, it is interpreted as a number.
- Letter M produces context-sensitive month names, such as the embedded form of names. Letter M is context-sensitive in the sense that when it is used in the standalone pattern, for example, "MMMM", it gives the standalone form of a month name and when it is used in the pattern containing other field(s), for example, "d MMMM", it gives the format form of a month name. For example, January in the Catalan language is "de gener" in the format form while it is "gener" in the standalone form. In this case, "MMMM" will produce "gener" and the month part of the "d MMMM" will produce "de gener". If a
DateFormatSymbols
has been set explicitly with constructorSimpleDateFormat(String,DateFormatSymbols)
or methodsetDateFormatSymbols(DateFormatSymbols)
, the month names given by theDateFormatSymbols
are used. - Letter L produces the standalone form of month names.
- Letter M produces context-sensitive month names, such as the embedded form of names. Letter M is context-sensitive in the sense that when it is used in the standalone pattern, for example, "MMMM", it gives the standalone form of a month name and when it is used in the pattern containing other field(s), for example, "d MMMM", it gives the format form of a month name. For example, January in the Catalan language is "de gener" in the format form while it is "gener" in the standalone form. In this case, "MMMM" will produce "gener" and the month part of the "d MMMM" will produce "de gener". If a
-
General time zone: Time zones are interpreted as text if they have names. For time zones representing a GMT offset value, the following syntax is 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 9
Hours 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.
-
RFC 822 time zone: For formatting, the RFC 822 4-digit time zone format is used:
RFC822TimeZone: Sign TwoDigitHours Minutes TwoDigitHours: Digit Digit
TwoDigitHours must be between 00 and 23. Other definitions are as for general time zones.For parsing, general time zones are also accepted.
-
ISO 8601 Time zone: The number of pattern letters designates the format for both formatting and parsing as follows:
ISO8601TimeZone: OneLetterISO8601TimeZone TwoLetterISO8601TimeZone ThreeLetterISO8601TimeZone OneLetterISO8601TimeZone: Sign TwoDigitHours Z TwoLetterISO8601TimeZone: Sign TwoDigitHours Minutes Z ThreeLetterISO8601TimeZone: Sign TwoDigitHours : Minutes Z
Other 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 aSimpleDateFormat
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. Examples
The following examples show how date and time patterns are interpreted in the U.S. locale. The given date and time are 2001-07-04 12:08:56 local time in the U.S. Pacific Time time zone.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 |
Synchronization
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.
- Since:
- 1.1
- See Also:
-
Java Tutorial,
Calendar
,TimeZone
,DateFormat
,DateFormatSymbols
, Serialized Form
Nested Class Summary
Nested classes/interfaces declared in class java.text.DateFormat
DateFormat.Field
Field Summary
Fields declared in 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
Constructor | Description |
---|---|
SimpleDateFormat() | Constructs a |
SimpleDateFormat(String pattern) | Constructs a |
SimpleDateFormat(String pattern,
DateFormatSymbols formatSymbols) | Constructs a |
SimpleDateFormat(String pattern,
Locale locale) | Constructs a |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | applyLocalizedPattern(String pattern) | Applies the given localized pattern string to this date format. |
void | applyPattern(String pattern) | Applies the given pattern string to this date format. |
Object | clone() | Creates a copy of this |
boolean | equals(Object obj) | Compares the given object with this |
StringBuffer | format(Date date,
StringBuffer toAppendTo,
FieldPosition pos) | Formats the given |
AttributedCharacterIterator | formatToCharacterIterator(Object obj) | Formats an Object producing an |
Date | get2DigitYearStart() | Returns the beginning date of the 100-year period 2-digit years are interpreted as being within. |
DateFormatSymbols | getDateFormatSymbols() | Gets a copy of the date and time format symbols of this date format. |
int | hashCode() | Returns the hash code value for this |
Date | parse(String text,
ParsePosition pos) | Parses text from a string to produce a |
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) | Sets the date and time format symbols of this date format. |
String | toLocalizedPattern() | Returns a localized pattern string describing this date format. |
String | toPattern() | Returns a pattern string describing this date format. |
Methods declared in 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 declared in class java.text.Format
format, parseObject
Methods declared in class java.lang.Object
finalize, getClass, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
SimpleDateFormat
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.
SimpleDateFormat
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))
.
- Parameters:
-
pattern
- the pattern describing the date and time format - Throws:
-
NullPointerException
- if the given pattern is null -
IllegalArgumentException
- if the given pattern is invalid - See Also:
-
Locale.getDefault(java.util.Locale.Category)
,Locale.Category.FORMAT
SimpleDateFormat
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.
- Parameters:
-
pattern
- the pattern describing the date and time format -
locale
- the locale whose date format symbols should be used - Throws:
-
NullPointerException
- if the given pattern or locale is null -
IllegalArgumentException
- if the given pattern is invalid
SimpleDateFormat
public SimpleDateFormat(String pattern, DateFormatSymbols formatSymbols)
Constructs a SimpleDateFormat
using the given pattern and date format symbols.
- Parameters:
-
pattern
- the pattern describing the date and time format -
formatSymbols
- the date format symbols to be used for formatting - Throws:
-
NullPointerException
- if the given pattern or formatSymbols is null -
IllegalArgumentException
- if the given pattern is invalid
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 rangestartDate
tostartDate + 100 years
. - Throws:
-
NullPointerException
- ifstartDate
isnull
. - Since:
- 1.2
- See Also:
get2DigitYearStart()
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
- Since:
- 1.2
- See Also:
set2DigitYearStart(java.util.Date)
format
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
.
- Specified by:
-
format
in 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
- keeps track on the position of the field within the returned string. For example, given a date-time text"1996.07.10 AD at 15:08:56 PDT"
, if the givenfieldPosition
isDateFormat.YEAR_FIELD
, the begin index and end index offieldPosition
will be set to 0 and 4, respectively. Notice that if the same date-time field appears more than once in a pattern, thefieldPosition
will be set for the first occurrence of that date-time field. For instance, formatting aDate
to the date-time string"1 PM PDT (Pacific Daylight Time)"
using the pattern"h a z (zzzz)"
and the alignment fieldDateFormat.TIMEZONE_FIELD
, the begin index and end index offieldPosition
will be set to 5 and 8, respectively, for the first occurrence of the timezone pattern character'z'
. - Returns:
- the formatted date-time string.
- Throws:
-
NullPointerException
- if any of the parameters isnull
.
formatToCharacterIterator
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.
- Overrides:
-
formatToCharacterIterator
in classFormat
- Parameters:
-
obj
- The object to format - Returns:
- AttributedCharacterIterator describing the formatted value.
- Throws:
-
NullPointerException
- if obj is null. -
IllegalArgumentException
- if the Format cannot format the given object, or if the Format's pattern string is invalid. - Since:
- 1.4
parse
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.
- Specified by:
-
parse
in classDateFormat
- Parameters:
-
text
- AString
, part of which should be parsed. -
pos
- AParsePosition
object with index and error index information as described above. - Returns:
- A
Date
parsed from the string. In case of error, returns null. - Throws:
-
NullPointerException
- iftext
orpos
is null.
toPattern
public String toPattern()
Returns a pattern string describing this date format.
- Returns:
- a pattern string describing this date format.
toLocalizedPattern
public String toLocalizedPattern()
Returns a localized pattern string describing this date format.
- Returns:
- a localized pattern string describing this date format.
applyPattern
public void applyPattern(String pattern)
Applies the given pattern string to this date format.
- Parameters:
-
pattern
- the new date and time pattern for this date format - Throws:
-
NullPointerException
- if the given pattern is null -
IllegalArgumentException
- if the given pattern is invalid
applyLocalizedPattern
public void applyLocalizedPattern(String pattern)
Applies the given localized pattern string to this date format.
- Parameters:
-
pattern
- a String to be mapped to the new date and time format pattern for this format - Throws:
-
NullPointerException
- if the given pattern is null -
IllegalArgumentException
- if the given pattern is invalid
getDateFormatSymbols
public DateFormatSymbols getDateFormatSymbols()
Gets a copy of the date and time format symbols of this date format.
- Returns:
- the date and time format symbols of this date format
- See Also:
setDateFormatSymbols(java.text.DateFormatSymbols)
setDateFormatSymbols
public void setDateFormatSymbols(DateFormatSymbols newFormatSymbols)
Sets the date and time format symbols of this date format.
- Parameters:
-
newFormatSymbols
- the new date and time format symbols - Throws:
-
NullPointerException
- if the given newFormatSymbols is null - See Also:
getDateFormatSymbols()
clone
public Object clone()
Creates a copy of this SimpleDateFormat
. This also clones the format's date format symbols.
- Overrides:
-
clone
in classDateFormat
- Returns:
- a clone of this
SimpleDateFormat
- See Also:
Cloneable
hashCode
public int hashCode()
Returns the hash code value for this SimpleDateFormat
object.
- Overrides:
-
hashCode
in classDateFormat
- Returns:
- the hash code value for this
SimpleDateFormat
object. - See Also:
-
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
equals
public boolean equals(Object obj)
Compares the given object with this SimpleDateFormat
for equality.
- Overrides:
-
equals
in classDateFormat
- Parameters:
-
obj
- the reference object with which to compare. - Returns:
- true if the given object is equal to this
SimpleDateFormat
- See Also:
-
Object.hashCode()
,HashMap