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java.text
public class: SimpleDateFormat [javadoc | source]
java.lang.Object
   java.text.Format
      java.text.DateFormat
         java.text.SimpleDateFormat

All Implemented Interfaces:
    Cloneable, Serializable

SimpleDateFormat is a concrete class for formatting and parsing dates in a locale-sensitive manner. It allows for formatting (date -> text), parsing (text -> date), and normalization.

SimpleDateFormat allows you to start by choosing any user-defined patterns for date-time formatting. However, you are encouraged to create a date-time formatter with either getTimeInstance, getDateInstance, or getDateTimeInstance in DateFormat. Each of these class methods can return a date/time formatter initialized with a default format pattern. You may modify the format pattern using the applyPattern methods as desired. For more information on using these methods, see DateFormat .

Date and Time Patterns

Date and time formats are specified by date and time pattern strings. Within date and time pattern strings, unquoted letters from 'A' to 'Z' and from 'a' to 'z' are interpreted as pattern letters representing the components of a date or time string. Text can be quoted using single quotes (') to avoid interpretation. "''" represents a single quote. All other characters are not interpreted; they're simply copied into the output string during formatting or matched against the input string during parsing.

The following pattern letters are defined (all other characters from 'A' to 'Z' and from 'a' to 'z' are reserved):

Letter Date or Time Component Presentation Examples
G Era designator Text AD
y Year Year 1996; 96
Y Week year Year 2009; 09
M Month in year Month July; Jul; 07
w Week in year Number 27
W Week in month Number 2
D Day in year Number 189
d Day in month Number 10
F Day of week in month Number 2
E Day name in week Text Tuesday; Tue
u Day number of week (1 = Monday, ..., 7 = Sunday) Number 1
a Am/pm marker Text PM
H Hour in day (0-23) Number 0
k Hour in day (1-24) Number 24
K Hour in am/pm (0-11) Number 0
h Hour in am/pm (1-12) Number 12
m Minute in hour Number 30
s Second in minute Number 55
S Millisecond Number 978
z Time zone General time zone Pacific Standard Time; PST; GMT-08:00
Z Time zone RFC 822 time zone -0800
X Time zone ISO 8601 time zone -08; -0800; -08:00
Pattern letters are usually repeated, as their number determines the exact presentation: SimpleDateFormat also supports localized date and time pattern strings. In these strings, the pattern letters described above may be replaced with other, locale dependent, pattern letters. SimpleDateFormat does not deal with the localization of text other than the pattern letters; that's up to the client of the class.

Examples

The following examples show how date and time patterns are interpreted in the U.S. locale. The given date and time are 2001-07-04 12:08:56 local time in the U.S. Pacific Time time zone.
Date and Time Pattern Result
"yyyy.MM.dd G 'at' HH:mm:ss z" 2001.07.04 AD at 12:08:56 PDT
"EEE, MMM d, ''yy" Wed, Jul 4, '01
"h:mm a" 12:08 PM
"hh 'o''clock' a, zzzz" 12 o'clock PM, Pacific Daylight Time
"K:mm a, z" 0:08 PM, PDT
"yyyyy.MMMMM.dd GGG hh:mm aaa" 02001.July.04 AD 12:08 PM
"EEE, d MMM yyyy HH:mm:ss Z" Wed, 4 Jul 2001 12:08:56 -0700
"yyMMddHHmmssZ" 010704120856-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSZ" 2001-07-04T12:08:56.235-0700
"yyyy-MM-dd'T'HH:mm:ss.SSSXXX" 2001-07-04T12:08:56.235-07:00
"YYYY-'W'ww-u" 2001-W27-3

Synchronization

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.

Field Summary
static final  long serialVersionUID     
static final  int currentSerialVersion     
transient  boolean useDateFormatSymbols    Indicates whether this SimpleDateFormat should use the DateFormatSymbols. If true, the format and parse methods use the DateFormatSymbols values. If false, the format and parse methods call Calendar.getDisplayName or Calendar.getDisplayNames. 
Fields inherited from java.text.DateFormat:
calendar,  numberFormat,  ERA_FIELD,  YEAR_FIELD,  MONTH_FIELD,  DATE_FIELD,  HOUR_OF_DAY1_FIELD,  HOUR_OF_DAY0_FIELD,  MINUTE_FIELD,  SECOND_FIELD,  MILLISECOND_FIELD,  DAY_OF_WEEK_FIELD,  DAY_OF_YEAR_FIELD,  DAY_OF_WEEK_IN_MONTH_FIELD,  WEEK_OF_YEAR_FIELD,  WEEK_OF_MONTH_FIELD,  AM_PM_FIELD,  HOUR1_FIELD,  HOUR0_FIELD,  TIMEZONE_FIELD,  FULL,  LONG,  MEDIUM,  SHORT,  DEFAULT
Constructor:
 public SimpleDateFormat() 
 public SimpleDateFormat(String pattern) 
    Constructs a SimpleDateFormat using the given pattern and the default date format symbols for the default locale. Note: This constructor may not support all locales. For full coverage, use the factory methods in the DateFormat class.
    Parameters:
    pattern - the pattern describing the date and time format
    Throws:
    NullPointerException - if the given pattern is null
    IllegalArgumentException - if the given pattern is invalid
    exception: NullPointerException - if the given pattern is null
    exception: IllegalArgumentException - if the given pattern is invalid
 public SimpleDateFormat(String pattern,
    Locale locale) 
    Constructs a SimpleDateFormat using the given pattern and the default date format symbols for the given locale. Note: This constructor may not support all locales. For full coverage, use the factory methods in the DateFormat class.
    Parameters:
    pattern - the pattern describing the date and time format
    locale - the locale whose date format symbols should be used
    Throws:
    NullPointerException - if the given pattern or locale is null
    IllegalArgumentException - if the given pattern is invalid
    exception: NullPointerException - if the given pattern or locale is null
    exception: IllegalArgumentException - if the given pattern is invalid
 public SimpleDateFormat(String pattern,
    DateFormatSymbols formatSymbols) 
    Constructs a SimpleDateFormat using the given pattern and date format symbols.
    Parameters:
    pattern - the pattern describing the date and time format
    formatSymbols - the date format symbols to be used for formatting
    Throws:
    NullPointerException - if the given pattern or formatSymbols is null
    IllegalArgumentException - if the given pattern is invalid
    exception: NullPointerException - if the given pattern or formatSymbols is null
    exception: IllegalArgumentException - if the given pattern is invalid
 SimpleDateFormat(int timeStyle,
    int dateStyle,
    Locale loc) 
Method from java.text.SimpleDateFormat Summary:
applyLocalizedPattern,   applyPattern,   clone,   equals,   format,   formatToCharacterIterator,   get2DigitYearStart,   getDateFormatSymbols,   hashCode,   parse,   set2DigitYearStart,   setDateFormatSymbols,   toLocalizedPattern,   toPattern
Methods from java.text.DateFormat:
clone,   equals,   format,   format,   format,   getAvailableLocales,   getCalendar,   getDateInstance,   getDateInstance,   getDateInstance,   getDateTimeInstance,   getDateTimeInstance,   getDateTimeInstance,   getInstance,   getNumberFormat,   getTimeInstance,   getTimeInstance,   getTimeInstance,   getTimeZone,   hashCode,   isLenient,   parse,   parse,   parseObject,   setCalendar,   setLenient,   setNumberFormat,   setTimeZone
Methods from java.text.Format:
clone,   createAttributedCharacterIterator,   createAttributedCharacterIterator,   createAttributedCharacterIterator,   createAttributedCharacterIterator,   format,   format,   formatToCharacterIterator,   parseObject,   parseObject
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.text.SimpleDateFormat Detail:
 public  void applyLocalizedPattern(String pattern) 
    Applies the given localized pattern string to this date format.
 public  void applyPattern(String pattern) 
    Applies the given pattern string to this date format.
 public Object clone() 
    Creates a copy of this SimpleDateFormat. This also clones the format's date format symbols.
 public boolean equals(Object obj) 
    Compares the given object with this SimpleDateFormat for equality.
 public StringBuffer format(Date date,
    StringBuffer toAppendTo,
    FieldPosition pos) 
    Formats the given Date into a date/time string and appends the result to the given StringBuffer.
 public AttributedCharacterIterator formatToCharacterIterator(Object obj) 
    Formats an Object producing an AttributedCharacterIterator. You can use the returned AttributedCharacterIterator to build the resulting String, as well as to determine information about the resulting String.

    Each attribute key of the AttributedCharacterIterator will be of type DateFormat.Field, with the corresponding attribute value being the same as the attribute key.

 public Date get2DigitYearStart() 
    Returns the beginning date of the 100-year period 2-digit years are interpreted as being within.
 public DateFormatSymbols getDateFormatSymbols() 
    Gets a copy of the date and time format symbols of this date format.
 public int hashCode() 
    Returns the hash code value for this SimpleDateFormat object.
 public Date parse(String text,
    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.

    This parsing operation uses the calendar to produce a {@code Date}. All of the {@code calendar}'s date-time fields are {@linkplain Calendar#clear() cleared} before parsing, and the {@code calendar}'s default values of the date-time fields are used for any missing date-time information. For example, the year value of the parsed {@code Date} is 1970 with GregorianCalendar if no year value is given from the parsing operation. The {@code TimeZone} value may be overwritten, depending on the given pattern and the time zone value in {@code text}. Any {@code TimeZone} value that has previously been set by a call to setTimeZone may need to be restored for further operations.

 public  void set2DigitYearStart(Date startDate) 
    Sets the 100-year period 2-digit years will be interpreted as being in to begin on the date the user specifies.
 public  void setDateFormatSymbols(DateFormatSymbols newFormatSymbols) 
    Sets the date and time format symbols of this date format.
 public String toLocalizedPattern() 
    Returns a localized pattern string describing this date format.
 public String toPattern() 
    Returns a pattern string describing this date format.