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.
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:
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 | |||||||||||
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DateFormat.Field | Defines constants that are used as attribute keys in the
AttributedCharacterIterator returned
from DateFormat.formatToCharacterIterator and as
field identifiers in FieldPosition . |
Constants | |||||||||||
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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 | |||||||||||
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calendar | The calendar that DateFormat uses to produce the time field
values needed to implement date and time formatting. |
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numberFormat | The number formatter that DateFormat uses to format numbers
in dates and times. |
Protected Constructors | |||||||||||
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Create a new date format.
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Public Methods | |||||||||||
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Overrides Cloneable
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Overrides equals
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Formats a Date into a date/time string.
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Overrides Format.
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Formats a Date into a date/time string.
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Returns an array of all locales for which the
get*Instance methods of this class can return
localized instances. | |||||||||||
Gets the calendar associated with this date/time formatter.
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Gets the date formatter with the given formatting style
for the default locale.
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Gets the date formatter with the given formatting style
for the given locale.
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Gets the date formatter with the default formatting style
for the default locale.
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Gets the date/time formatter with the given formatting styles
for the given locale.
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Gets the date/time formatter with the given date and time
formatting styles for the default locale.
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Gets the date/time formatter with the default formatting style
for the default locale.
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Get a default date/time formatter that uses the SHORT style for both the
date and the time.
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Gets the number formatter which this date/time formatter uses to
format and parse a time.
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Gets the time formatter with the given formatting style
for the default locale.
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Gets the time formatter with the default formatting style
for the default locale.
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Gets the time formatter with the given formatting style
for the given locale.
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Gets the time zone.
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Overrides hashCode
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Tell whether date/time parsing is to be lenient.
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Parses text from the beginning of the given string to produce a date.
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Parse a date/time string according to the given parse position.
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Parses text from a string to produce a
Date . | |||||||||||
Set the calendar to be used by this date format.
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Specify whether or not date/time parsing is to be lenient.
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Allows you to set the number formatter.
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Sets the time zone for the calendar of this DateFormat object.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.text.Format
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From class
java.lang.Object
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Useful constant for AM_PM field alignment. Used in FieldPosition of date/time formatting.
Useful constant for DATE field alignment. Used in FieldPosition of date/time formatting.
Useful constant for DAY_OF_WEEK field alignment. Used in FieldPosition of date/time formatting.
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. Used in FieldPosition of date/time formatting.
Useful constant for DAY_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.
Constant for default style pattern. Its value is MEDIUM.
Useful constant for ERA field alignment. Used in FieldPosition of date/time formatting.
Constant for full style pattern.
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.
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.
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.
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 for long style pattern.
Constant for medium style pattern.
Useful constant for MILLISECOND field alignment. Used in FieldPosition of date/time formatting.
Useful constant for MINUTE field alignment. Used in FieldPosition of date/time formatting.
Useful constant for MONTH field alignment. Used in FieldPosition of date/time formatting.
Useful constant for SECOND field alignment. Used in FieldPosition of date/time formatting.
Constant for short style pattern.
Useful constant for TIMEZONE field alignment. Used in FieldPosition of date/time formatting.
Useful constant for WEEK_OF_MONTH field alignment. Used in FieldPosition of date/time formatting.
Useful constant for WEEK_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.
Useful constant for YEAR field alignment. Used in FieldPosition of date/time formatting.
The calendar that DateFormat
uses to produce the time field
values needed to implement date and time formatting. Subclasses should
initialize this to a calendar appropriate for the locale associated with
this DateFormat
.
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
.
Create a new date format.
Overrides equals
obj | the reference object with which to compare. |
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true
if this object is the same as the obj
argument; false
otherwise.Formats a Date into a date/time string.
date | a Date to be formatted into a date/time string. |
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toAppendTo | the string buffer for the returning date/time string. |
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'. |
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.
obj | must be a Number or a Date. |
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toAppendTo | the string buffer for the returning time string. |
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'. |
Formats a Date into a date/time string.
date | the time value to be formatted into a time string. |
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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
.
DateFormat
instances are available.
Gets the calendar associated with this date/time formatter.
Gets the date formatter with the given formatting style for the default locale.
style | the given formatting style. For example, SHORT for "M/d/yy" in the US locale. |
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Gets the date formatter with the given formatting style for the given locale.
style | the given formatting style. For example, SHORT for "M/d/yy" in the US locale. |
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aLocale | the given locale. |
Gets the date formatter with the default formatting style for the default locale.
Gets the date/time formatter with the given formatting styles for the given locale.
dateStyle | the given date formatting style. |
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timeStyle | the given time formatting style. |
aLocale | the given locale. |
Gets the date/time formatter with the given date and time formatting styles for the default locale.
dateStyle | the given date formatting style. For example, SHORT for "M/d/yy" in the US locale. |
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timeStyle | the given time formatting style. For example, SHORT for "h:mm a" in the US locale. |
Gets the date/time formatter with the default formatting style for the default locale.
Get a default date/time formatter that uses the SHORT style for both the date and the time.
Gets the number formatter which this date/time formatter uses to format and parse a time.
Gets the time formatter with the given formatting style for the default locale.
style | the given formatting style. For example, SHORT for "h:mm a" in the US locale. |
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Gets the time formatter with the default formatting style for the default locale.
Gets the time formatter with the given formatting style for the given locale.
style | the given formatting style. For example, SHORT for "h:mm a" in the US locale. |
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aLocale | the given locale. |
Gets the time zone.
Overrides hashCode
Tell whether date/time parsing is to be lenient.
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.
source | A String whose beginning should be parsed. |
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Date
parsed from the string.ParseException | if the beginning of the specified string cannot be parsed. |
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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).
source | The date/time string to be parsed |
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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. |
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.
source | A String , part of which should be parsed. |
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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 pos is null.
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Set the calendar to be used by this date format. Initially, the default calendar for the specified or default locale is used.
newCalendar | the new Calendar to be used by the date format |
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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.
lenient | when true, parsing is lenient |
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Allows you to set the number formatter.
newNumberFormat | the given new NumberFormat. |
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Sets the time zone for the calendar of this DateFormat object.
zone | the given new time zone. |
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