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Class java.text.DateFormat

java.lang.Object
   |
   +----java.text.Format
           |
           +----java.text.DateFormat

public class DateFormat
extends Format
implements Cloneable

DateFormat is an abstract base class that defines the programming interface for formatting and parsing a date or time in a locale-sensitive manner.

Subclasses of DateFormat, such as SimpleDateFormat, allow for formatting (millis -> text), parsing (text -> millis), and normalization.

DateFormat provides many class methods for obtaining default date/time formatters based on the default locale or a specified 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 class getXxxxxInstance methods or the getInstance method. For example,

 myString = DateFormat.getDateInstance().format(myDate);

If you are formatting multiple numbers, 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 < a.length; ++i) {
      output.println(df.format(myDate[i]) + "; ");
  }

To format a number for a different locale, specify it in the call to getXxxxxInstance or getInstance.

 DateFormat df = DateFormat.getDateInstance(Locale.FRANCE);

You can use a DateInstance to parse also.

 myDate = df.parse(myString);

Use getDateInstance to get the normal date format for that country. 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 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

progressively parse through pieces of a string.
align any particular field, or find out where it is for selection on the screen.

See Also:: Format, NumberFormat, SimpleDateFormat, Calendar, GregorianCalendar, TimeZone

AM_PM_FIELD: Useful constant for AM_PM field alignment.
calendar: The calendar that DateFormat uses to produce the time field values needed to implement date/time formatting.
DATE_FIELD: Useful constant for DATE field alignment.
DAY_OF_WEEK_FIELD: Useful constant for DAY_OF_WEEK field alignment.
DAY_OF_WEEK_IN_MONTH_FIELD: Useful constant for DAY_OF_WEEK_IN_MONTH field alignment.
DAY_OF_YEAR_FIELD: Useful constant for DAY_OF_YEAR field alignment.
DEFAULT: Constant for default style pattern.
ERA_FIELD: Useful constant for ERA field alignment.
FULL: Constant for full style pattern.
HOUR0_FIELD: Useful constant for zero-based HOUR field alignment.
HOUR1_FIELD: Useful constant for one-based HOUR field alignment.
HOUR_OF_DAY0_FIELD: Useful constant for zero-based HOUR_OF_DAY field alignment.
HOUR_OF_DAY1_FIELD: Useful constant for one-based HOUR_OF_DAY field alignment.
LONG: Constant for long style pattern.
MEDIUM: Constant for medium style pattern.
MILLISECOND_FIELD: Useful constant for MILLISECOND field alignment.
MINUTE_FIELD: Useful constant for MINUTE field alignment.
MONTH_FIELD: Useful constant for MONTH field alignment.
numberFormat: The number formatter that DateFormat uses to format numbers in dates and times.
SECOND_FIELD: Useful constant for SECOND field alignment.
SHORT: Constant for short style pattern.
TIMEZONE_FIELD: Useful constant for TIMEZONE field alignment.
WEEK_OF_MONTH_FIELD: Useful constant for WEEK_OF_MONTH field alignment.
WEEK_OF_YEAR_FIELD: Useful constant for WEEK_OF_YEAR field alignment.
YEAR_FIELD: Useful constant for YEAR field alignment.

DateFormat()

clone(): Overrides Cloneable
equals(Object): Overrides equals
format(Date): Formats a Date into a date/time string.
format(Date, StringBuffer, FieldPosition): Formats a Date into a date/time string.
format(Object, StringBuffer, FieldPosition): Overrides Format.
getAvailableLocales(): Gets the set of locales for which DateFormats are installed.
getCalendar(): Gets the calendar associated with this date/time formatter.
getDateInstance(): Gets the date formatter with the default formatting style for the default locale.
getDateInstance(int): Gets the date formatter with the given formatting style for the default locale.
getDateInstance(int, Locale): Gets the date formatter with the given formatting style for the given locale.
getDateTimeInstance(): Gets the date/time formatter with the default formatting style for the default locale.
getDateTimeInstance(int, int): Gets the date/time formatter with the given date and time formatting styles for the default locale.
getDateTimeInstance(int, int, Locale): Gets the date/time formatter with the given formatting styles for the given locale.
getInstance(): Get a default date/time formatter that uses the SHORT style for both the date and the time.
getNumberInstance(): Gets the number formatter which this date/time formatter uses to format and parse a time.
getTimeInstance(): Gets the time formatter with the default formatting style for the default locale.
getTimeInstance(int): Gets the time formatter with the given formatting style for the default locale.
getTimeInstance(int, Locale): Gets the time formatter with the given formatting style for the given locale.
getTimeZone(): Gets the time zone.
hashCode(): Overrides hashCode
isLenient(): Tell whether date/time parsing is to be lenient.
parse(String): Parse a date/time string.
parse(String, ParsePosition): Parse a date/time string according to the given parse position.
parseObject(String, ParsePosition): Parse a date/time string into an Object.
setCalendar(Calendar): Set the calendar to be used by this date format.
setLenient(boolean): Specify whether or not date/time parsing is to be lenient.
setNumberFormat(NumberFormat): Allows you to set the number formatter.
setTimeZone(TimeZone): Sets the time zone for the calendar of this DateFormat object.

calendar

  protected Calendar calendar

The calendar that DateFormat uses to produce the time field values needed to implement date/time formatting. Subclasses should initialize this to the default calendar for the locale associated with this DateFormat.

numberFormat

  protected NumberFormat numberFormat

The number formatter that DateFormat uses to format numbers in dates and times. Subclasses should initialize this to the default number format for the locale associated with this DateFormat.

ERA_FIELD

  public final static int ERA_FIELD

Useful constant for ERA field alignment. Used in FieldPosition of date/time formatting.

YEAR_FIELD

  public final static int YEAR_FIELD

Useful constant for YEAR field alignment. Used in FieldPosition of date/time formatting.

MONTH_FIELD

  public final static int MONTH_FIELD

Useful constant for MONTH field alignment. Used in FieldPosition of date/time formatting.

DATE_FIELD

  public final static int DATE_FIELD

Useful constant for DATE field alignment. Used in FieldPosition of date/time formatting.

HOUR_OF_DAY1_FIELD

  public final static 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.

HOUR_OF_DAY0_FIELD

  public final static 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.

MINUTE_FIELD

  public final static int MINUTE_FIELD

Useful constant for MINUTE field alignment. Used in FieldPosition of date/time formatting.

SECOND_FIELD

  public final static int SECOND_FIELD

Useful constant for SECOND field alignment. Used in FieldPosition of date/time formatting.

MILLISECOND_FIELD

  public final static int MILLISECOND_FIELD

Useful constant for MILLISECOND field alignment. Used in FieldPosition of date/time formatting.

DAY_OF_WEEK_FIELD

  public final static int DAY_OF_WEEK_FIELD

Useful constant for DAY_OF_WEEK field alignment. Used in FieldPosition of date/time formatting.

DAY_OF_YEAR_FIELD

  public final static int DAY_OF_YEAR_FIELD

Useful constant for DAY_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.

DAY_OF_WEEK_IN_MONTH_FIELD

  public final static int DAY_OF_WEEK_IN_MONTH_FIELD

Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. Used in FieldPosition of date/time formatting.

WEEK_OF_YEAR_FIELD

  public final static int WEEK_OF_YEAR_FIELD

Useful constant for WEEK_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.

WEEK_OF_MONTH_FIELD

  public final static int WEEK_OF_MONTH_FIELD

Useful constant for WEEK_OF_MONTH field alignment. Used in FieldPosition of date/time formatting.

AM_PM_FIELD

  public final static int AM_PM_FIELD

Useful constant for AM_PM field alignment. Used in FieldPosition of date/time formatting.

HOUR1_FIELD

  public final static 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.

HOUR0_FIELD

  public final static 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.

TIMEZONE_FIELD

  public final static int TIMEZONE_FIELD

Useful constant for TIMEZONE field alignment. Used in FieldPosition of date/time formatting.

FULL

  public final static int FULL

Constant for full style pattern.

LONG

  public final static int LONG

Constant for long style pattern.

MEDIUM

  public final static int MEDIUM

Constant for medium style pattern.

SHORT

  public final static int SHORT

Constant for short style pattern.

DEFAULT

  public final static int DEFAULT

Constant for default style pattern.

DateFormat

  protected DateFormat()

format

  public final 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 - must be a Number or a Date.; toAppendTo - the string buffer for the returning time string.; fieldPosition - the field. On input: an alignment field, if desired. On output: the offsets of the alignment field.
Returns:: the formatted time string.
Overrides:: format in class Format
See Also:: Format

format

  public abstract StringBuffer format(Date date,
                                      StringBuffer toAppendTo,
                                      FieldPosition fieldPosition)

Formats a Date into a date/time string.

Parameters:: date - a Date to be formatted into a date/time string.; toAppendTo - the string buffer for the returning date/time string.; fieldPosition - the field. 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.field is DateFormat.YEAR_FIELD, the offsets fieldPosition.beginIndex and fieldPosition.getEndIndex 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 occurence 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 offsets fieldPosition.beginIndex and fieldPosition.getEndIndex will be set to 5 and 8, respectively, for the first occurence of the time zone pattern character 'z'.
Returns:: the formatted date/time string.

format

  public final String format(Date date)

Formats a Date into a date/time string.

Parameters:: date - the time value to be formatted into a time string.
Returns:: the formatted time string.

parse

  public Date parse(String text) throws ParseException

Parse a date/time string.

Throws: ParseException: If the given string cannot be parsed as a date.
See Also:: parse

parse

  public abstract Date parse(String text,
                             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(837039928046).

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).

Parameters:: text - The date/time string to be parsed; pos - 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:: A Date, or null if the input could not be parsed
See Also:: setLenient

parseObject

  public Object parseObject(String source,
                            ParsePosition pos)

Parse a date/time string into an Object. This convenience method simply calls parse(String, ParsePosition).

Overrides:: parseObject in class Format
See Also:: parse

getTimeInstance

  public final static DateFormat getTimeInstance()

Gets the time formatter with the default formatting style for the default locale.

Returns:: a time formatter.

getTimeInstance

  public final static DateFormat getTimeInstance(int style)

Gets the time formatter with the given formatting style for the default locale.

Parameters:: style - the given formatting style. For example, SHORT for "h:mm a" in the US locale.
Returns:: a time formatter.

getTimeInstance

  public final static DateFormat getTimeInstance(int style,
                                                 Locale aLocale)

Gets the time formatter with the given formatting style for the given locale.

Parameters:: style - the given formatting style. For example, SHORT for "h:mm a" in the US locale.; inLocale - the given locale.
Returns:: a time formatter.

getDateInstance

  public final static DateFormat getDateInstance()

Gets the date formatter with the default formatting style for the default locale.

Returns:: a date formatter.

getDateInstance

  public final static DateFormat getDateInstance(int style)

Gets the date formatter with the given formatting style for the default locale.

Parameters:: style - the given formatting style. For example, SHORT for "M/d/yy" in the US locale.
Returns:: a date formatter.

getDateInstance

  public final static DateFormat getDateInstance(int style,
                                                 Locale aLocale)

Gets the date formatter with the given formatting style for the given locale.

Parameters:: style - the given formatting style. For example, SHORT for "M/d/yy" in the US locale.; inLocale - the given locale.
Returns:: a date formatter.

getDateTimeInstance

  public final static DateFormat getDateTimeInstance()

Gets the date/time formatter with the default formatting style for the default locale.

Returns:: a date/time formatter.

getDateTimeInstance

  public final static 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 - 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.
Returns:: a date/time formatter.

getDateTimeInstance

  public final static DateFormat getDateTimeInstance(int dateStyle,
                                                     int timeStyle,
                                                     Locale aLocale)

Gets the date/time formatter with the given formatting styles for the given locale.

Parameters:: dateStyle - the given date formatting style.; timeStyle - the given time formatting style.; inLocale - the given locale.
Returns:: a date/time formatter.

getInstance

  public final static DateFormat getInstance()

Get a default date/time formatter that uses the SHORT style for both the date and the time.

getAvailableLocales

  public static Locale[] getAvailableLocales()

Gets the set of locales for which DateFormats are installed.

Returns:: the set of locales for which DateFormats are installed.

setCalendar

  public 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.

getCalendar

  public Calendar getCalendar()

Gets the calendar associated with this date/time formatter.

Returns:: the calendar associated with this date/time formatter.

setNumberFormat

  public void setNumberFormat(NumberFormat newNumberFormat)

Allows you to set the number formatter.

Parameters:: newNumberFormat - the given new NumberFormat.

getNumberInstance

  public NumberFormat getNumberInstance()

Gets the number formatter which this date/time formatter uses to format and parse a time.

Returns:: the number formatter which this date/time formatter uses.

setTimeZone

  public void setTimeZone(TimeZone zone)

Sets the time zone for the calendar of this DateFormat object.

Parameters:: zone - the given new time zone.

getTimeZone

  public TimeZone getTimeZone()

Gets the time zone.

Returns:: the time zone associated with the calendar of DateFormat.

setLenient

  public 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.

See Also:: setLenient

isLenient

  public boolean isLenient()

Tell whether date/time parsing is to be lenient.

hashCode

  public int hashCode()

Overrides hashCode

Overrides:: hashCode in class Object

equals

  public boolean equals(Object obj)

Overrides equals

Overrides:: equals in class Object

clone

  public Object clone()

Overrides Cloneable

Overrides:: clone in class Format

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