public
abstract
class
DateFormat
extends Format
| java.lang.Object | ||
| ↳ | java.text.Format | |
| ↳ | java.text.DateFormat | |
 Known Direct Subclasses
|
DateFormat is an abstract class for date/time formatting subclasses which
formats and parses dates or time in a language-independent manner.
The date/time formatting subclass, such as SimpleDateFormat, allows for
formatting (i.e., date -> text), parsing (text -> date), and
normalization. The date is represented as a Date object or
as the milliseconds since January 1, 1970, 00:00:00 GMT.
DateFormat provides many class methods for obtaining default date/time
formatters based on the default or a given locale and a number of formatting
styles. The formatting styles include FULL, LONG, MEDIUM, and SHORT. More
detail and examples of using these styles are provided in the method
descriptions.
DateFormat helps you to format and parse dates for any locale.
Your code can be completely independent of the locale conventions for
months, days of the week, or even the calendar format: lunar vs. solar.
To format a date for the current Locale, use one of the static factory methods:
myString = DateFormat.getDateInstance().format(myDate);
If you are formatting multiple dates, it is more efficient to get the format and use it multiple times so that the system doesn't have to fetch the information about the local language and country conventions multiple times.
Developers
DateFormat df = DateFormat.getDateInstance();
for (int i = 0; i < myDate.length; ++i) {
output.println(df.format(myDate[i]) + "; ");
}
To format a date for a different Locale, specify it in the
call to getDateInstance().
DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE);
You can use a DateFormat to parse also.
myDate = df.parse(myString);
Use getDateInstance to get the normal date format for that country.
There are other static factory methods available.
Use getTimeInstance to get the time format for that country.
Use getDateTimeInstance to get a date and time format. You can pass in
different options to these factory methods to control the length of the
result; from SHORT to MEDIUM to LONG to FULL. The exact result depends
on the locale, but generally:
SHORT is completely numeric, such as 12.13.52 or 3:30pm
MEDIUM is longer, such as Jan 12, 1952
LONG is longer, such as January 12, 1952 or 3:30:32pm
FULL is pretty completely specified, such as
Tuesday, April 12, 1952 AD or 3:30:42pm PST.
You can also set the time zone on the format if you wish.
If you want even more control over the format or parsing,
(or want to give your users more control),
you can try casting the DateFormat you get from the factory methods
to a SimpleDateFormat. This will work for the majority
of countries; just remember to put it in a try block in case you
encounter an unusual one.
You can also use forms of the parse and format methods with
ParsePosition and FieldPosition to
allow you to
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.
Nested classes | |
|---|---|
class |
DateFormat.Field
Defines constants that are used as attribute keys in the
|
Constants | |
|---|---|
int |
AM_PM_FIELD
Useful constant for AM_PM field alignment. |
int |
DATE_FIELD
Useful constant for DATE field alignment. |
int |
DAY_OF_WEEK_FIELD
Useful constant for DAY_OF_WEEK field alignment. |
int |
DAY_OF_WEEK_IN_MONTH_FIELD
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. |
int |
DAY_OF_YEAR_FIELD
Useful constant for DAY_OF_YEAR field alignment. |
int |
DEFAULT
Constant for default style pattern. |
int |
ERA_FIELD
Useful constant for ERA field alignment. |
int |
FULL
Constant for full style pattern. |
int |
HOUR0_FIELD
Useful constant for zero-based HOUR field alignment. |
int |
HOUR1_FIELD
Useful constant for one-based HOUR field alignment. |
int |
HOUR_OF_DAY0_FIELD
Useful constant for zero-based HOUR_OF_DAY field alignment. |
int |
HOUR_OF_DAY1_FIELD
Useful constant for one-based HOUR_OF_DAY field alignment. |
int |
LONG
Constant for long style pattern. |
int |
MEDIUM
Constant for medium style pattern. |
int |
MILLISECOND_FIELD
Useful constant for MILLISECOND field alignment. |
int |
MINUTE_FIELD
Useful constant for MINUTE field alignment. |
int |
MONTH_FIELD
Useful constant for MONTH field alignment. |
int |
SECOND_FIELD
Useful constant for SECOND field alignment. |
int |
SHORT
Constant for short style pattern. |
int |
TIMEZONE_FIELD
Useful constant for TIMEZONE field alignment. |
int |
WEEK_OF_MONTH_FIELD
Useful constant for WEEK_OF_MONTH field alignment. |
int |
WEEK_OF_YEAR_FIELD
Useful constant for WEEK_OF_YEAR field alignment. |
int |
YEAR_FIELD
Useful constant for YEAR field alignment. |
Fields | |
|---|---|
protected
Calendar |
calendar
The |
protected
NumberFormat |
numberFormat
The number formatter that |
Protected constructors | |
|---|---|
DateFormat()
Create a new date format. |
|
Public methods | |
|---|---|
Object
|
clone()
Overrides Cloneable |
boolean
|
equals(Object obj)
Overrides equals |
final
StringBuffer
|
format(Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
Overrides Format. |
abstract
StringBuffer
|
format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
Formats a Date into a date/time string. |
final
String
|
format(Date date)
Formats a Date into a date/time string. |
static
Locale[]
|
getAvailableLocales()
Returns an array of all locales for which the
|
Calendar
|
getCalendar()
Gets the calendar associated with this date/time formatter. |
static
final
DateFormat
|
getDateInstance(int style, Locale aLocale)
Gets the date formatter with the given formatting style for the given locale. |
static
final
DateFormat
|
getDateInstance(int style)
Gets the date formatter with the given formatting style for the default locale. |
static
final
DateFormat
|
getDateInstance()
Gets the date formatter with the default formatting style for the default locale. |
static
final
DateFormat
|
getDateTimeInstance(int dateStyle, int timeStyle)
Gets the date/time formatter with the given date and time formatting styles for the default locale. |
static
final
DateFormat
|
getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
Gets the date/time formatter with the given formatting styles for the given locale. |
static
final
DateFormat
|
getDateTimeInstance()
Gets the date/time formatter with the default formatting style for the default locale. |
static
final
DateFormat
|
getInstance()
Get a default date/time formatter that uses the SHORT style for both the date and the time. |
NumberFormat
|
getNumberFormat()
Gets the number formatter which this date/time formatter uses to format and parse a time. |
static
final
DateFormat
|
getTimeInstance(int style)
Gets the time formatter with the given formatting style for the default locale. |
static
final
DateFormat
|
getTimeInstance(int style, Locale aLocale)
Gets the time formatter with the given formatting style for the given locale. |
static
final
DateFormat
|
getTimeInstance()
Gets the time formatter with the default formatting style for the default locale. |
TimeZone
|
getTimeZone()
Gets the time zone. |
int
|
hashCode()
Overrides hashCode |
boolean
|
isLenient()
Tell whether date/time parsing is to be lenient. |
Date
|
parse(String source)
Parses text from the beginning of the given string to produce a date. |
abstract
Date
|
parse(String source, ParsePosition pos)
Parse a date/time string according to the given parse position. |
Object
|
parseObject(String source, ParsePosition pos)
Parses text from a string to produce a |
void
|
setCalendar(Calendar newCalendar)
Set the calendar to be used by this date format. |
void
|
setLenient(boolean lenient)
Specify whether or not date/time parsing is to be lenient. |
void
|
setNumberFormat(NumberFormat newNumberFormat)
Allows you to set the number formatter. |
void
|
setTimeZone(TimeZone zone)
Sets the time zone for the calendar of this |
Inherited methods | |
|---|---|
From
class
java.text.Format
| |
From
class
java.lang.Object
| |
int AM_PM_FIELD
Useful constant for AM_PM field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 14 (0x0000000e)
int DATE_FIELD
Useful constant for DATE field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 3 (0x00000003)
int DAY_OF_WEEK_FIELD
Useful constant for DAY_OF_WEEK field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 9 (0x00000009)
int DAY_OF_WEEK_IN_MONTH_FIELD
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 11 (0x0000000b)
int DAY_OF_YEAR_FIELD
Useful constant for DAY_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 10 (0x0000000a)
int DEFAULT
Constant for default style pattern. Its value is MEDIUM.
Constant Value: 2 (0x00000002)
int ERA_FIELD
Useful constant for ERA field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 0 (0x00000000)
int HOUR0_FIELD
Useful constant for zero-based HOUR field alignment. Used in FieldPosition of date/time formatting. HOUR0_FIELD is used for the zero-based 12-hour clock. For example, 11:30 PM + 1 hour results in 00:30 AM.
Constant Value: 16 (0x00000010)
int HOUR1_FIELD
Useful constant for one-based HOUR field alignment. Used in FieldPosition of date/time formatting. HOUR1_FIELD is used for the one-based 12-hour clock. For example, 11:30 PM + 1 hour results in 12:30 AM.
Constant Value: 15 (0x0000000f)
int HOUR_OF_DAY0_FIELD
Useful constant for zero-based HOUR_OF_DAY field alignment. Used in FieldPosition of date/time formatting. HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock. For example, 23:59 + 01:00 results in 00:59.
Constant Value: 5 (0x00000005)
int HOUR_OF_DAY1_FIELD
Useful constant for one-based HOUR_OF_DAY field alignment. Used in FieldPosition of date/time formatting. HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock. For example, 23:59 + 01:00 results in 24:59.
Constant Value: 4 (0x00000004)
int MEDIUM
Constant for medium style pattern.
Constant Value: 2 (0x00000002)
int MILLISECOND_FIELD
Useful constant for MILLISECOND field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 8 (0x00000008)
int MINUTE_FIELD
Useful constant for MINUTE field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 6 (0x00000006)
int MONTH_FIELD
Useful constant for MONTH field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 2 (0x00000002)
int SECOND_FIELD
Useful constant for SECOND field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 7 (0x00000007)
int SHORT
Constant for short style pattern.
Constant Value: 3 (0x00000003)
int TIMEZONE_FIELD
Useful constant for TIMEZONE field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 17 (0x00000011)
int WEEK_OF_MONTH_FIELD
Useful constant for WEEK_OF_MONTH field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 13 (0x0000000d)
int WEEK_OF_YEAR_FIELD
Useful constant for WEEK_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 12 (0x0000000c)
int YEAR_FIELD
Useful constant for YEAR field alignment. Used in FieldPosition of date/time formatting.
Constant Value: 1 (0x00000001)
Calendar calendar
The Calendar instance used for calculating the date-time fields
and the instant of time. This field is used for both formatting and
parsing.
Subclasses should initialize this field to a Calendar
appropriate for the Locale associated with this
DateFormat.
NumberFormat numberFormat
The number formatter that DateFormat uses to format numbers
in dates and times. Subclasses should initialize this to a number format
appropriate for the locale associated with this DateFormat.
Object clone ()
Overrides Cloneable
| Returns | |
|---|---|
Object |
a clone of this instance. |
boolean equals (Object obj)
Overrides equals
| Parameters | |
|---|---|
obj |
Object:
the reference object with which to compare. |
| Returns | |
|---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
StringBuffer format (Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
Overrides Format. Formats a time object into a time string. Examples of time objects are a time value expressed in milliseconds and a Date object.
| Parameters | |
|---|---|
obj |
Object:
must be a Number or a Date. |
toAppendTo |
StringBuffer:
the string buffer for the returning time string. |
fieldPosition |
FieldPosition:
keeps track of the position of the field
within the returned string.
On input: an alignment field,
if desired. On output: the offsets of the alignment field. For
example, given a time text "1996.07.10 AD at 15:08:56 PDT",
if the given fieldPosition is DateFormat.YEAR_FIELD, the
begin index and end index of fieldPosition will be set to
0 and 4, respectively.
Notice that if the same time field appears
more than once in a pattern, the fieldPosition will be set for the first
occurrence of that time field. For instance, formatting a Date to
the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
"h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
the begin index and end index of fieldPosition will be set to
5 and 8, respectively, for the first occurrence of the timezone
pattern character 'z'. |
| Returns | |
|---|---|
StringBuffer |
the string buffer passed in as toAppendTo, with formatted text appended. |
See also:
StringBuffer format (Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
Formats a Date into a date/time string.
| Parameters | |
|---|---|
date |
Date:
a Date to be formatted into a date/time string. |
toAppendTo |
StringBuffer:
the string buffer for the returning date/time string. |
fieldPosition |
FieldPosition:
keeps track of the position of the field
within the returned string.
On input: an alignment field,
if desired. On output: the offsets of the alignment field. For
example, given a time text "1996.07.10 AD at 15:08:56 PDT",
if the given fieldPosition is DateFormat.YEAR_FIELD, the
begin index and end index of fieldPosition will be set to
0 and 4, respectively.
Notice that if the same time field appears
more than once in a pattern, the fieldPosition will be set for the first
occurrence of that time field. For instance, formatting a Date to
the time string "1 PM PDT (Pacific Daylight Time)" using the pattern
"h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD,
the begin index and end index of fieldPosition will be set to
5 and 8, respectively, for the first occurrence of the timezone
pattern character 'z'. |
| Returns | |
|---|---|
StringBuffer |
the string buffer passed in as toAppendTo, with formatted text appended. |
String format (Date date)
Formats a Date into a date/time string.
| Parameters | |
|---|---|
date |
Date:
the time value to be formatted into a time string. |
| Returns | |
|---|---|
String |
the formatted time string. |
Locale[] getAvailableLocales ()
Returns an array of all locales for which the
get*Instance methods of this class can return
localized instances.
The returned array represents the union of locales supported by the Java
runtime and by installed
DateFormatProvider implementations.
It must contain at least a Locale instance equal to
Locale.US.
| Returns | |
|---|---|
Locale[] |
An array of locales for which localized
DateFormat instances are available.
|
Calendar getCalendar ()
Gets the calendar associated with this date/time formatter.
| Returns | |
|---|---|
Calendar |
the calendar associated with this date/time formatter. |
DateFormat getDateInstance (int style, Locale aLocale)
Gets the date formatter with the given formatting style for the given locale.
| Parameters | |
|---|---|
style |
int:
the given formatting style. For example,
SHORT for "M/d/yy" in the US locale. |
aLocale |
Locale:
the given locale. |
| Returns | |
|---|---|
DateFormat |
a date formatter. |
DateFormat getDateInstance (int style)
Gets the date formatter with the given formatting style for the default locale.
| Parameters | |
|---|---|
style |
int:
the given formatting style. For example,
SHORT for "M/d/yy" in the US locale. |
| Returns | |
|---|---|
DateFormat |
a date formatter. |
DateFormat getDateInstance ()
Gets the date formatter with the default formatting style for the default locale.
| Returns | |
|---|---|
DateFormat |
a date formatter. |
DateFormat getDateTimeInstance (int dateStyle, int timeStyle)
Gets the date/time formatter with the given date and time formatting styles for the default locale.
| Parameters | |
|---|---|
dateStyle |
int:
the given date formatting style. For example,
SHORT for "M/d/yy" in the US locale. |
timeStyle |
int:
the given time formatting style. For example,
SHORT for "h:mm a" in the US locale. |
| Returns | |
|---|---|
DateFormat |
a date/time formatter. |
DateFormat getDateTimeInstance (int dateStyle, int timeStyle, Locale aLocale)
Gets the date/time formatter with the given formatting styles for the given locale.
| Parameters | |
|---|---|
dateStyle |
int:
the given date formatting style. |
timeStyle |
int:
the given time formatting style. |
aLocale |
Locale:
the given locale. |
| Returns | |
|---|---|
DateFormat |
a date/time formatter. |
DateFormat getDateTimeInstance ()
Gets the date/time formatter with the default formatting style for the default locale.
| Returns | |
|---|---|
DateFormat |
a date/time formatter. |
DateFormat getInstance ()
Get a default date/time formatter that uses the SHORT style for both the date and the time.
| Returns | |
|---|---|
DateFormat |
|
NumberFormat getNumberFormat ()
Gets the number formatter which this date/time formatter uses to format and parse a time.
| Returns | |
|---|---|
NumberFormat |
the number formatter which this date/time formatter uses. |
DateFormat getTimeInstance (int style)
Gets the time formatter with the given formatting style for the default locale.
| Parameters | |
|---|---|
style |
int:
the given formatting style. For example,
SHORT for "h:mm a" in the US locale. |
| Returns | |
|---|---|
DateFormat |
a time formatter. |
DateFormat getTimeInstance (int style, Locale aLocale)
Gets the time formatter with the given formatting style for the given locale.
| Parameters | |
|---|---|
style |
int:
the given formatting style. For example,
SHORT for "h:mm a" in the US locale. |
aLocale |
Locale:
the given locale. |
| Returns | |
|---|---|
DateFormat |
a time formatter. |
DateFormat getTimeInstance ()
Gets the time formatter with the default formatting style for the default locale.
| Returns | |
|---|---|
DateFormat |
a time formatter. |
TimeZone getTimeZone ()
Gets the time zone. This method is equivalent to the following call.
getCalendar().getTimeZone()
| Returns | |
|---|---|
TimeZone |
the time zone associated with the calendar of DateFormat. |
int hashCode ()
Overrides hashCode
| Returns | |
|---|---|
int |
a hash code value for this object. |
boolean isLenient ()
Tell whether date/time parsing is to be lenient. This method is equivalent to the following call.
getCalendar().isLenient()
| Returns | |
|---|---|
boolean |
true if the calendar is lenient;
false otherwise. |
See also:
Date parse (String source)
Parses text from the beginning of the given string to produce a date. The method may not use the entire text of the given string.
See the parse(String, ParsePosition) method for more information
on date parsing.
| Parameters | |
|---|---|
source |
String:
A String whose beginning should be parsed. |
| Returns | |
|---|---|
Date |
A Date parsed from the string. |
| Throws | |
|---|---|
ParseException |
if the beginning of the specified string cannot be parsed. |
Date parse (String source, ParsePosition pos)
Parse a date/time string according to the given parse position. For
example, a time text "07/10/96 4:5 PM, PDT" will be parsed into a Date
that is equivalent to Date(837039900000L).
By default, parsing is lenient: If the input is not in the form used
by this object's format method but can still be parsed as a date, then
the parse succeeds. Clients may insist on strict adherence to the
format by calling setLenient(false).
This parsing operation uses the calendar to produce
a Date. As a result, the calendar's date-time
fields and the TimeZone value may have been
overwritten, depending on subclass implementations. Any TimeZone value that has previously been set by a call to
setTimeZone may need
to be restored for further operations.
| Parameters | |
|---|---|
source |
String:
The date/time string to be parsed |
pos |
ParsePosition:
On input, the position at which to start parsing; on
output, the position at which parsing terminated, or the
start position if the parse failed. |
| Returns | |
|---|---|
Date |
A Date, or null if the input could not be parsed
|
Object parseObject (String source, 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.
See the parse(String, ParsePosition) method for more information
on date parsing.
| Parameters | |
|---|---|
source |
String:
A String, part of which should be parsed. |
pos |
ParsePosition:
A ParsePosition object with index and error
index information as described above. |
| Returns | |
|---|---|
Object |
A Date parsed from the string. In case of
error, returns null. |
| Throws | |
|---|---|
NullPointerException |
if pos is null.
|
void setCalendar (Calendar newCalendar)
Set the calendar to be used by this date format. Initially, the default calendar for the specified or default locale is used.
Any TimeZone and leniency values that have previously been set are
overwritten by newCalendar's values.
| Parameters | |
|---|---|
newCalendar |
Calendar:
the new Calendar to be used by the date format
|
void setLenient (boolean lenient)
Specify whether or not date/time parsing is to be lenient. With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. With strict parsing, inputs must match this object's format.
This method is equivalent to the following call.
getCalendar().setLenient(lenient)
This leniency value is overwritten by a call to setCalendar().
| Parameters | |
|---|---|
lenient |
boolean:
when true, parsing is lenient |
See also:
void setNumberFormat (NumberFormat newNumberFormat)
Allows you to set the number formatter.
| Parameters | |
|---|---|
newNumberFormat |
NumberFormat:
the given new NumberFormat.
|
void setTimeZone (TimeZone zone)
Sets the time zone for the calendar of this DateFormat object.
This method is equivalent to the following call.
getCalendar().setTimeZone(zone)
The TimeZone set by this method is overwritten by a
setCalendar call.
The TimeZone set by this method may be overwritten as
a result of a call to the parse method.
| Parameters | |
|---|---|
zone |
TimeZone:
the given new time zone.
|