java.lang.Object java.text.Format java.text.DateFormat
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 < a.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 Class Summary | |
---|---|
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. |
Field Summary | |
---|---|
static int |
AM_PM_FIELD
Useful constant for AM_PM field alignment. |
protected Calendar |
calendar
The calendar that DateFormat uses to produce the time field values needed to implement date and time formatting. |
static int |
DATE_FIELD
Useful constant for DATE field alignment. |
static int |
DAY_OF_WEEK_FIELD
Useful constant for DAY_OF_WEEK field alignment. |
static int |
DAY_OF_WEEK_IN_MONTH_FIELD
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. |
static int |
DAY_OF_YEAR_FIELD
Useful constant for DAY_OF_YEAR field alignment. |
static int |
DEFAULT
Constant for default style pattern. |
static int |
ERA_FIELD
Useful constant for ERA field alignment. |
static int |
FULL
Constant for full style pattern. |
static int |
HOUR_OF_DAY0_FIELD
Useful constant for zero-based HOUR_OF_DAY field alignment. |
static int |
HOUR_OF_DAY1_FIELD
Useful constant for one-based HOUR_OF_DAY field alignment. |
static int |
HOUR0_FIELD
Useful constant for zero-based HOUR field alignment. |
static int |
HOUR1_FIELD
Useful constant for one-based HOUR field alignment. |
static int |
LONG
Constant for long style pattern. |
static int |
MEDIUM
Constant for medium style pattern. |
static int |
MILLISECOND_FIELD
Useful constant for MILLISECOND field alignment. |
static int |
MINUTE_FIELD
Useful constant for MINUTE field alignment. |
static 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 int |
SECOND_FIELD
Useful constant for SECOND field alignment. |
static int |
SHORT
Constant for short style pattern. |
static int |
TIMEZONE_FIELD
Useful constant for TIMEZONE field alignment. |
static int |
WEEK_OF_MONTH_FIELD
Useful constant for WEEK_OF_MONTH field alignment. |
static int |
WEEK_OF_YEAR_FIELD
Useful constant for WEEK_OF_YEAR field alignment. |
static int |
YEAR_FIELD
Useful constant for YEAR field alignment. |
Constructor Summary | |
---|---|
protected |
DateFormat
() Create a new date format. |
Method Summary | |
---|---|
Object |
clone
() Overrides Cloneable |
boolean |
equals
(
Object
obj) Overrides equals |
String |
format
(
Date
date) Formats a Date into a date/time string. |
abstract StringBuffer |
format
(
Date
date,
StringBuffer
toAppendTo,
FieldPosition
fieldPosition) Formats a Date into a date/time string. |
StringBuffer |
format
(
Object
obj,
StringBuffer
toAppendTo,
FieldPosition
fieldPosition) Overrides Format. |
static Locale |
getAvailableLocales
() Returns an array |
Calendar |
getCalendar
() Gets the calendar associated with this date/time formatter. |
static DateFormat |
getDateInstance
() Gets the date formatter with the default formatting style for the default locale. |
static DateFormat |
getDateInstance
(int style) Gets the date formatter with the given formatting style for the default locale. |
static DateFormat |
getDateInstance
(int style,
Locale
aLocale) Gets the date formatter with the given formatting style for the given locale. |
static DateFormat |
getDateTimeInstance
() Gets the date/time formatter with the default formatting style for the default locale. |
static DateFormat |
getDateTimeInstance
(int dateStyle, int timeStyle) Gets the date/time formatter with the given date and time formatting styles for the default locale. |
static DateFormat |
getDateTimeInstance
(int dateStyle, int timeStyle,
Locale
aLocale) Gets the date/time formatter with the given formatting styles for the given locale. |
static 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 DateFormat |
getTimeInstance
() Gets the time formatter with the default formatting style for the default locale. |
static DateFormat |
getTimeInstance
(int style) Gets the time formatter with the given formatting style for the default locale. |
static DateFormat |
getTimeInstance
(int style,
Locale
aLocale) 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
(
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 Date. |
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 DateFormat object. |
Methods inherited from class java.text. Format |
---|
format , formatToCharacterIterator , parseObject |
Methods inherited from class java.lang. Object |
---|
finalize , getClass , notify , notifyAll , toString , wait , wait , wait |
Field Detail |
---|
protected Calendar calendar
protected NumberFormat numberFormat
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
Constructor Detail |
---|
protected DateFormat()
Method Detail |
---|
public final StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
public abstract StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
public final String format(Date date)
public Date parse(String source) throws ParseException
See the parse(String, ParsePosition) method for more information on date parsing.
public abstract Date parse(String source, ParsePosition pos)
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).
public Object parseObject(String source, ParsePosition pos)
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.
public static final DateFormat getTimeInstance()
public static final DateFormat getTimeInstance(int style)
public static final DateFormat getTimeInstance(int style, Locale aLocale)
public static final DateFormat getDateInstance()
public static final DateFormat getDateInstance(int style)
public static final DateFormat getDateInstance(int style, Locale aLocale)
public static final DateFormat getDateTimeInstance()
public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle)
public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
public static final DateFormat getInstance()
public static Locale[] getAvailableLocales()
public void setCalendar(Calendar newCalendar)
public Calendar getCalendar()
public void setNumberFormat(NumberFormat newNumberFormat)
public NumberFormat getNumberFormat()
public void setTimeZone(TimeZone zone)
public TimeZone getTimeZone()
public void setLenient(boolean lenient)
public boolean isLenient()
public int hashCode()
public boolean equals(Object obj)
public Object clone()