Serializable
, Cloneable
SimpleDateFormat
public abstract class DateFormat extends Format
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.
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);
If the specified locale contains "ca" (calendar), "rg" (region override), and/or "tz" (timezone) Unicode extensions, the calendar, the country and/or the time zone for formatting are overridden. If both "ca" and "rg" are specified, the calendar from the "ca" extension supersedes the implicit one from the "rg" extension.
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.
DateTimeFormatter
as an immutable and thread-safe alternative.format(Date, StringBuffer, FieldPosition)
and parse(String, ParsePosition)
methods may throw NullPointerException
, if any of their parameter is null
. The subclass may provide its own implementation and specification about NullPointerException
.setCalendar(Calendar)
, setNumberFormat(NumberFormat)
and setTimeZone(TimeZone)
methods do not throw NullPointerException
when their parameter is null
, but any subsequent operations on the same instance may throw NullPointerException
.getCalendar()
, getNumberFormat()
and getTimeZone()
methods may return null
, if the respective values of this instance is set to null
through the corresponding setter methods. For Example: getTimeZone()
may return null
, if the TimeZone
value of this instance is set as setTimeZone(null)
.Modifier and Type | Class | Description |
---|---|---|
static class |
DateFormat.Field |
Defines constants that are used as attribute keys in the AttributedCharacterIterator returned from DateFormat.formatToCharacterIterator and as field identifiers in FieldPosition . |
Modifier and Type | Field | Description |
---|---|---|
static final int |
AM_PM_FIELD |
Useful constant for AM_PM field alignment. |
protected Calendar |
calendar |
The Calendar instance used for calculating the date-time fields and the instant of time. |
static final int |
DATE_FIELD |
Useful constant for DATE field alignment. |
static final int |
DAY_OF_WEEK_FIELD |
Useful constant for DAY_OF_WEEK field alignment. |
static final int |
DAY_OF_WEEK_IN_MONTH_FIELD |
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. |
static final int |
DAY_OF_YEAR_FIELD |
Useful constant for DAY_OF_YEAR field alignment. |
static final int |
DEFAULT |
Constant for default style pattern. |
static final int |
ERA_FIELD |
Useful constant for ERA field alignment. |
static final int |
FULL |
Constant for full style pattern. |
static final int |
HOUR_OF_DAY0_FIELD |
Useful constant for zero-based HOUR_OF_DAY field alignment. |
static final int |
HOUR_OF_DAY1_FIELD |
Useful constant for one-based HOUR_OF_DAY field alignment. |
static final int |
HOUR0_FIELD |
Useful constant for zero-based HOUR field alignment. |
static final int |
HOUR1_FIELD |
Useful constant for one-based HOUR field alignment. |
static final int |
LONG |
Constant for long style pattern. |
static final int |
MEDIUM |
Constant for medium style pattern. |
static final int |
MILLISECOND_FIELD |
Useful constant for MILLISECOND field alignment. |
static final int |
MINUTE_FIELD |
Useful constant for MINUTE field alignment. |
static final int |
MONTH_FIELD |
Useful constant for MONTH field alignment. |
protected NumberFormat |
numberFormat |
The number formatter that DateFormat uses to format numbers in dates and times. |
static final int |
SECOND_FIELD |
Useful constant for SECOND field alignment. |
static final int |
SHORT |
Constant for short style pattern. |
static final int |
TIMEZONE_FIELD |
Useful constant for TIMEZONE field alignment. |
static final int |
WEEK_OF_MONTH_FIELD |
Useful constant for WEEK_OF_MONTH field alignment. |
static final int |
WEEK_OF_YEAR_FIELD |
Useful constant for WEEK_OF_YEAR field alignment. |
static final int |
YEAR_FIELD |
Useful constant for YEAR field alignment. |
Modifier | Constructor | Description |
---|---|---|
protected |
Create a new date format. |
Modifier and Type | Method | Description |
---|---|---|
Object |
clone() |
Overrides Cloneable |
boolean |
equals |
Overrides equals |
final StringBuffer |
format |
Formats the given Object into a date-time string. |
final String |
format |
Formats a Date into a date-time string. |
abstract StringBuffer |
format |
Formats a Date into a date-time string. |
static Locale[] |
getAvailableLocales() |
Returns an array of all locales for which the get*Instance methods of this class can return localized instances. |
Calendar |
getCalendar() |
Gets the calendar associated with this date/time formatter. |
static final DateFormat |
getDateInstance() |
Gets the date formatter with the default formatting style for the default FORMAT locale. |
static final DateFormat |
getDateInstance |
Gets the date formatter with the given formatting style for the default FORMAT locale. |
static final DateFormat |
getDateInstance |
Gets the date formatter with the given formatting style for the given locale. |
static final DateFormat |
getDateTimeInstance() |
Gets the date/time formatter with the default formatting style for the default FORMAT locale. |
static final DateFormat |
getDateTimeInstance |
Gets the date/time formatter with the given date and time formatting styles for the default FORMAT locale. |
static final DateFormat |
getDateTimeInstance |
Gets the date/time formatter with the given formatting styles for the given 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() |
Gets the time formatter with the default formatting style for the default FORMAT locale. |
static final DateFormat |
getTimeInstance |
Gets the time formatter with the given formatting style for the default FORMAT locale. |
static final DateFormat |
getTimeInstance |
Gets the time formatter with the given formatting style for the given locale. |
TimeZone |
getTimeZone() |
Gets the time zone. |
int |
hashCode() |
Overrides hashCode |
boolean |
isLenient() |
Tell whether date/time parsing is to be lenient. |
Date |
parse |
Parses text from the beginning of the given string to produce a date. |
abstract Date |
parse |
Parse a date/time string according to the given parse position. |
Object |
parseObject |
Parses text from a string to produce a Date . |
void |
setCalendar |
Set the calendar to be used by this date format. |
void |
setLenient |
Specify whether or not date/time parsing is to be lenient. |
void |
setNumberFormat |
Allows you to set the number formatter. |
void |
setTimeZone |
Sets the time zone for the calendar of this DateFormat object. |
format, formatToCharacterIterator, parseObject
protected Calendar calendar
protected NumberFormat numberFormat
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
.public static final int ERA_FIELD
public static final int YEAR_FIELD
public static final int MONTH_FIELD
public static final int DATE_FIELD
public static final int HOUR_OF_DAY1_FIELD
public static final int HOUR_OF_DAY0_FIELD
public static final int MINUTE_FIELD
public static final int SECOND_FIELD
public static final int MILLISECOND_FIELD
public static final int DAY_OF_WEEK_FIELD
public static final int DAY_OF_YEAR_FIELD
public static final int DAY_OF_WEEK_IN_MONTH_FIELD
public static final int WEEK_OF_YEAR_FIELD
public static final int WEEK_OF_MONTH_FIELD
public static final int AM_PM_FIELD
public static final int HOUR1_FIELD
public static final int HOUR0_FIELD
public static final int TIMEZONE_FIELD
public static final int FULL
public static final int LONG
public static final int MEDIUM
public static final int SHORT
public static final int DEFAULT
protected DateFormat()
public final StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
Object
into a date-time string. The formatted string is appended to the given StringBuffer
.format
in class Format
obj
- Must be a Date
or a Number
representing a millisecond offset from the Epoch.toAppendTo
- The string buffer for the returning date-time string.fieldPosition
- 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 given fieldPosition
is YEAR_FIELD
, the begin index and end index of fieldPosition
will be set to 0 and 4, respectively. Notice that if the same date-time field appears more than once in a pattern, the fieldPosition
will be set for the first occurrence of that date-time field. For instance, formatting a Date
to the date-time string "1 PM PDT (Pacific Daylight Time)"
using the pattern "h a z (zzzz)"
and the alignment field 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'
.toAppendTo
, with formatted text appended.IllegalArgumentException
- if the Format
cannot format the given obj
.public abstract StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
Date
into a date-time string. The formatted string is appended to the given StringBuffer
.date
- a Date to be formatted into a date-time string.toAppendTo
- the string buffer for the returning date-time string.fieldPosition
- 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 given fieldPosition
is YEAR_FIELD
, the begin index and end index of fieldPosition
will be set to 0 and 4, respectively. Notice that if the same date-time field appears more than once in a pattern, the fieldPosition
will be set for the first occurrence of that date-time field. For instance, formatting a Date
to the date-time string "1 PM PDT (Pacific Daylight Time)"
using the pattern "h a z (zzzz)"
and the alignment field 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'
.toAppendTo
, with formatted text appended.public final String format(Date date)
Date
into a date-time string.date
- the time value to be formatted into a date-time string.public Date parse(String source) throws ParseException
See the parse(String, ParsePosition)
method for more information on date parsing.
source
- A String
whose beginning should be parsed.Date
parsed from the string.ParseException
- if the beginning of the specified string cannot be parsed.public abstract Date parse(String source, ParsePosition pos)
"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.
source
- The date/time string to be parsedpos
- 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.Date
, or null
if the input could not be parsedpublic Object parseObject(String source, ParsePosition pos)
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.
parseObject
in class Format
source
- 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 source
or pos
is null.public static final DateFormat getTimeInstance()
FORMAT
locale. This is equivalent to calling getTimeInstance(DEFAULT,
Locale.getDefault(Locale.Category.FORMAT))
.
public static final DateFormat getTimeInstance(int style)
FORMAT
locale. This is equivalent to calling getTimeInstance(style,
Locale.getDefault(Locale.Category.FORMAT))
.
style
- the given formatting style. For example, SHORT for "h:mm a" in the US locale.public static final DateFormat getTimeInstance(int style, Locale aLocale)
style
- the given formatting style. For example, SHORT for "h:mm a" in the US locale.aLocale
- the given locale.public static final DateFormat getDateInstance()
FORMAT
locale. This is equivalent to calling getDateInstance(DEFAULT,
Locale.getDefault(Locale.Category.FORMAT))
.
public static final DateFormat getDateInstance(int style)
FORMAT
locale. This is equivalent to calling getDateInstance(style,
Locale.getDefault(Locale.Category.FORMAT))
.
style
- the given formatting style. For example, SHORT for "M/d/yy" in the US locale.public static final DateFormat getDateInstance(int style, Locale aLocale)
style
- the given formatting style. For example, SHORT for "M/d/yy" in the US locale.aLocale
- the given locale.public static final DateFormat getDateTimeInstance()
FORMAT
locale. This is equivalent to calling getDateTimeInstance(DEFAULT,
DEFAULT, Locale.getDefault(Locale.Category.FORMAT))
.
public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle)
FORMAT
locale. This is equivalent to calling getDateTimeInstance(dateStyle,
timeStyle, Locale.getDefault(Locale.Category.FORMAT))
.
dateStyle
- the given date formatting style. For example, SHORT for "M/d/yy" in the US locale.timeStyle
- the given time formatting style. For example, SHORT for "h:mm a" in the US locale.public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
dateStyle
- the given date formatting style.timeStyle
- the given time formatting style.aLocale
- the given locale.public static final DateFormat getInstance()
public static Locale[] getAvailableLocales()
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. At a minimum, the returned array must contain a Locale
instance equal to Locale.ROOT
and a Locale
instance equal to Locale.US
.DateFormat
instances are available.public void setCalendar(Calendar newCalendar)
Any TimeZone
and leniency values that have previously been set are overwritten by newCalendar
's values.
newCalendar
- the new Calendar
to be used by the date formatpublic Calendar getCalendar()
public void setNumberFormat(NumberFormat newNumberFormat)
newNumberFormat
- the given new NumberFormat.public NumberFormat getNumberFormat()
public void setTimeZone(TimeZone zone)
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.
zone
- the given new time zone.public TimeZone getTimeZone()
getCalendar().getTimeZone();
public void setLenient(boolean lenient)
This method is equivalent to the following call.
getCalendar().setLenient(lenient);
This leniency value is overwritten by a call to setCalendar()
.
lenient
- when true
, parsing is lenientpublic boolean isLenient()
getCalendar().isLenient();
true
if the calendar
is lenient; false
otherwise.public int hashCode()
public boolean equals(Object obj)
public Object clone()
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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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