IT. Expert System.

Android Reference

SimpleDateFormat


java.text

Class SimpleDateFormat

  • All Implemented Interfaces:
    Serializable, Cloneable


    public class SimpleDateFormat
    extends DateFormat
    A concrete class for formatting and parsing dates in a locale-sensitive manner. Formatting turns a Date into a String, and parsing turns a String into a Date.

    Time Pattern Syntax

    You can supply a pattern describing what strings are produced/accepted, but almost all callers should use DateFormat.getDateInstance(), DateFormat.getDateTimeInstance(), or DateFormat.getTimeInstance() to get a ready-made instance suitable for the user's locale.

    The main reason you'd create an instance this class directly is because you need to format/parse a specific machine-readable format, in which case you almost certainly want to explicitly ask for Locale.US to ensure that you get ASCII digits (rather than, say, Arabic digits). (See "Be wary of the default locale".) The most useful non-localized pattern is "yyyy-MM-dd HH:mm:ss.SSSZ", which corresponds to the ISO 8601 international standard date format.

    To specify the time format, use a time pattern string. In this string, any character from 'A' to 'Z' or 'a' to 'z' is treated specially. All other characters are passed through verbatim. The interpretation of each of the ASCII letters is given in the table below. ASCII letters not appearing in the table are reserved for future use, and it is an error to attempt to use them.

    Symbol Meaning Presentation Example
    D day in year (Number) 189
    E day of week (Text) Tuesday
    F day of week in month (Number) 2 (2nd Wed in July)
    G era designator (Text) AD
    H hour in day (0-23) (Number) 0
    K hour in am/pm (0-11) (Number) 0
    L stand-alone month (Text/Number) July / 07
    M month in year (Text/Number) July / 07
    S fractional seconds (Number) 978
    W week in month (Number) 2
    Z time zone (RFC 822) (Timezone) -0800
    a am/pm marker (Text) PM
    c stand-alone day of week (Text/Number) Tuesday / 2
    d day in month (Number) 10
    h hour in am/pm (1-12) (Number) 12
    k hour in day (1-24) (Number) 24
    m minute in hour (Number) 30
    s second in minute (Number) 55
    w week in year (Number) 27
    y year (Number) 2010
    z time zone (Timezone) Pacific Standard Time
    ' escape for text (Delimiter) 'Date='
    '' single quote (Literal) 'o''clock'

    The number of consecutive copies (the "count") of a pattern character further influences the format.

    • Text if the count is 4 or more, use the full form; otherwise use a short or abbreviated form if one exists. So zzzz might give Pacific Standard Time whereas z might give PST. Note that the count does not specify the exact width of the field.
    • Number the count is the minimum number of digits. Shorter values are zero-padded to this width, longer values overflow this width.

      Years are handled specially: yy truncates to the last 2 digits, but any other number of consecutive ys does not truncate. So where yyyy or y might give 2010, yy would give 10.

      Fractional seconds are also handled specially: they're zero-padded on the right.

    • Text/Number: if the count is 3 or more, use text; otherwise use a number. So MM might give 07 while MMM gives July.

    The two pattern characters L and c are ICU-compatible extensions, not available in the RI. These are necessary for correct localization in languages such as Russian that distinguish between, say, "June" and "June 2010".

    When numeric fields are adjacent directly, with no intervening delimiter characters, they constitute a run of adjacent numeric fields. Such runs are parsed specially. For example, the format "HHmmss" parses the input text "123456" to 12:34:56, parses the input text "12345" to 1:23:45, and fails to parse "1234". In other words, the leftmost field of the run is flexible, while the others keep a fixed width. If the parse fails anywhere in the run, then the leftmost field is shortened by one character, and the entire run is parsed again. This is repeated until either the parse succeeds or the leftmost field is one character in length. If the parse still fails at that point, the parse of the run fails.

    See set2DigitYearStart(java.util.Date) for more about handling two-digit years.

    Sample Code

    If you're formatting for human use, you should use an instance returned from DateFormat as described above. This code:

     DateFormat[] formats = new DateFormat[] {
       DateFormat.getDateInstance(),
       DateFormat.getDateTimeInstance(),
       DateFormat.getTimeInstance(),
     };
     for (DateFormat df : formats) {
       System.err.println(df.format(new Date(0)));
     }
     

    Produces this output when run on an en_US device in the PDT time zone:

     Dec 31, 1969
     Dec 31, 1969 4:00:00 PM
     4:00:00 PM
     
    And will produce similarly appropriate localized human-readable output on any user's system.

    If you're formatting for machine use, consider this code:

     String[] formats = new String[] {
       "yyyy-MM-dd",
       "yyyy-MM-dd HH:mm",
       "yyyy-MM-dd HH:mmZ",
       "yyyy-MM-dd HH:mm:ss.SSSZ",
       "yyyy-MM-dd'T'HH:mm:ss.SSSZ",
     };
     for (String format : formats) {
       SimpleDateFormat sdf = new SimpleDateFormat(format, Locale.US);
       System.err.format("%30s %s\n", format, sdf.format(new Date(0)));
       sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
       System.err.format("%30s %s\n", format, sdf.format(new Date(0)));
     }
     

    Which produces this output when run in the PDT time zone:

                         yyyy-MM-dd 1969-12-31
                         yyyy-MM-dd 1970-01-01
                   yyyy-MM-dd HH:mm 1969-12-31 16:00
                   yyyy-MM-dd HH:mm 1970-01-01 00:00
                  yyyy-MM-dd HH:mmZ 1969-12-31 16:00-0800
                  yyyy-MM-dd HH:mmZ 1970-01-01 00:00+0000
           yyyy-MM-dd HH:mm:ss.SSSZ 1969-12-31 16:00:00.000-0800
           yyyy-MM-dd HH:mm:ss.SSSZ 1970-01-01 00:00:00.000+0000
         yyyy-MM-dd'T'HH:mm:ss.SSSZ 1969-12-31T16:00:00.000-0800
         yyyy-MM-dd'T'HH:mm:ss.SSSZ 1970-01-01T00:00:00.000+0000
     

    As this example shows, each SimpleDateFormat instance has a TimeZone. This is because it's called upon to format instances of Date, which represents an absolute time in UTC. That is, Date does not carry time zone information. By default, SimpleDateFormat will use the system's default time zone. This is appropriate for human-readable output (for which, see the previous sample instead), but generally inappropriate for machine-readable output, where ambiguity is a problem. Note that in this example, the output that included a time but no time zone cannot be parsed back into the original Date. For this reason it is almost always necessary and desirable to include the timezone in the output. It may also be desirable to set the formatter's time zone to UTC (to ease comparison, or to make logs more readable, for example).

    Synchronization

    SimpleDateFormat is not thread-safe. Users should create a separate instance for each thread.
    See Also:
    Calendar, Date, TimeZone, DateFormat, Serialized Form
    • Constructor Detail

      • SimpleDateFormat

        public SimpleDateFormat()
        Constructs a new SimpleDateFormat for formatting and parsing dates and times in the SHORT style for the user's default locale. See "Be wary of the default locale".
      • SimpleDateFormat

        public SimpleDateFormat(String pattern)
        Constructs a new SimpleDateFormat using the specified non-localized pattern and the DateFormatSymbols and Calendar for the user's default locale. See "Be wary of the default locale".
        Parameters:
        pattern - the pattern.
        Throws:
        NullPointerException - if the pattern is null.
        IllegalArgumentException - if pattern is not considered to be usable by this formatter.
      • SimpleDateFormat

        public SimpleDateFormat(String template,
                        Locale locale)
        Constructs a new SimpleDateFormat using the specified non-localized pattern and the DateFormatSymbols and Calendar for the specified locale.
        Parameters:
        template - the pattern.
        locale - the locale.
        Throws:
        NullPointerException - if the pattern is null.
        IllegalArgumentException - if the pattern is invalid.
    • Method Detail

      • applyLocalizedPattern

        public void applyLocalizedPattern(String template)
        Changes the pattern of this simple date format to the specified pattern which uses localized pattern characters.
        Parameters:
        template - the localized pattern.
      • applyPattern

        public void applyPattern(String template)
        Changes the pattern of this simple date format to the specified pattern which uses non-localized pattern characters.
        Parameters:
        template - the non-localized pattern.
        Throws:
        NullPointerException - if the pattern is null.
        IllegalArgumentException - if the pattern is invalid.
      • clone

        public Object clone()
        Returns a new SimpleDateFormat with the same pattern and properties as this simple date format.
        Overrides:
        clone in class DateFormat
        Returns:
        a shallow copy of this format.
        See Also:
        Cloneable
      • equals

        public boolean equals(Object object)
        Compares the specified object with this simple date format and indicates if they are equal. In order to be equal, object must be an instance of SimpleDateFormat and have the same DateFormat properties, pattern, DateFormatSymbols and creation year.
        Overrides:
        equals in class DateFormat
        Parameters:
        object - the object to compare with this object.
        Returns:
        true if the specified object is equal to this simple date format; false otherwise.
        See Also:
        hashCode()
      • formatToCharacterIterator

        public AttributedCharacterIterator formatToCharacterIterator(Object object)
        Formats the specified object using the rules of this simple date format and returns an AttributedCharacterIterator with the formatted date and attributes.
        Overrides:
        formatToCharacterIterator in class Format
        Parameters:
        object - the object to format.
        Returns:
        an AttributedCharacterIterator with the formatted date and attributes.
        Throws:
        NullPointerException - if the object is null.
        IllegalArgumentException - if the object cannot be formatted by this simple date format.
      • format

        public StringBuffer format(Date date,
                          StringBuffer buffer,
                          FieldPosition fieldPos)
        Formats the specified date as a string using the pattern of this date format and appends the string to the specified string buffer.

        If the field member of field contains a value specifying a format field, then its beginIndex and endIndex members will be updated with the position of the first occurrence of this field in the formatted text.

        Specified by:
        format in class DateFormat
        Parameters:
        date - the date to format.
        buffer - the target string buffer to append the formatted date/time to.
        fieldPos - on input: an optional alignment field; on output: the offsets of the alignment field in the formatted text.
        Returns:
        the string buffer.
        Throws:
        IllegalArgumentException - if there are invalid characters in the pattern.
      • get2DigitYearStart

        public Date get2DigitYearStart()
        Returns the date which is the start of the one hundred year period for two-digit year values. See set2DigitYearStart(java.util.Date) for details.
      • getDateFormatSymbols

        public DateFormatSymbols getDateFormatSymbols()
        Returns the DateFormatSymbols used by this simple date format.
        Returns:
        the DateFormatSymbols object.
      • hashCode

        public int hashCode()
        Description copied from class: Object
        Returns an integer hash code for this object. By contract, any two objects for which Object.equals(java.lang.Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

        Note that hash values must not change over time unless information used in equals comparisons also changes.

        See Writing a correct hashCode method if you intend implementing your own hashCode method.

        Overrides:
        hashCode in class DateFormat
        Returns:
        this object's hash code.
        See Also:
        Object.equals(java.lang.Object)
      • parse

        public Date parse(String string,
                 ParsePosition position)
        Parses a date from the specified string starting at the index specified by position. If the string is successfully parsed then the index of the ParsePosition is updated to the index following the parsed text. On error, the index is unchanged and the error index of ParsePosition is set to the index where the error occurred.
        Specified by:
        parse in class DateFormat
        Parameters:
        string - the string to parse using the pattern of this simple date format.
        position - input/output parameter, specifies the start index in string from where to start parsing. If parsing is successful, it is updated with the index following the parsed text; on error, the index is unchanged and the error index is set to the index where the error occurred.
        Returns:
        the date resulting from the parse, or null if there is an error.
        Throws:
        IllegalArgumentException - if there are invalid characters in the pattern.
      • set2DigitYearStart

        public void set2DigitYearStart(Date date)
        Sets the date which is the start of the one hundred year period for two-digit year values.

        When parsing a date string using the abbreviated year pattern yy, SimpleDateFormat must interpret the abbreviated year relative to some century. It does this by adjusting dates to be within 80 years before and 20 years after the time the SimpleDateFormat instance was created. For example, using a pattern of MM/dd/yy, an instance created on Jan 1, 1997 would interpret the string "01/11/12" as Jan 11, 2012 but interpret the string "05/04/64" as May 4, 1964. During parsing, only strings consisting of exactly two digits, as defined by Character.isDigit(char), will be parsed into the default century. Any other numeric string, such as a one digit string, a three or more digit string, or a two digit string that isn't all digits (for example, "-1"), is interpreted literally. So using the same pattern, both "01/02/3" and "01/02/003" are parsed as Jan 2, 3 AD. Similarly, "01/02/-3" is parsed as Jan 2, 4 BC.

        If the year pattern does not have exactly two 'y' characters, the year is interpreted literally, regardless of the number of digits. So using the pattern MM/dd/yyyy, "01/11/12" is parsed as Jan 11, 12 A.D.

      • setDateFormatSymbols

        public void setDateFormatSymbols(DateFormatSymbols value)
        Sets the DateFormatSymbols used by this simple date format.
        Parameters:
        value - the new DateFormatSymbols object.
      • toLocalizedPattern

        public String toLocalizedPattern()
        Returns the pattern of this simple date format using localized pattern characters.
        Returns:
        the localized pattern.
      • toPattern

        public String toPattern()
        Returns the pattern of this simple date format using non-localized pattern characters.
        Returns:
        the non-localized pattern.


Content

Android Reference

Java basics

Java Enterprise Edition (EE)

Java Standard Edition (SE)

SQL

HTML

PHP

CSS

Java Script

MYSQL

JQUERY

VBS

REGEX

C

C++

C#

Design patterns

RFC (standard status)

RFC (proposed standard status)

RFC (draft standard status)

RFC (informational status)

RFC (experimental status)

RFC (best current practice status)

RFC (historic status)

RFC (unknown status)

IT dictionary

License.
All information of this service is derived from the free sources and is provided solely in the form of quotations. This service provides information and interfaces solely for the familiarization (not ownership) and under the "as is" condition.
Copyright 2016 © ELTASK.COM. All rights reserved.
Site is optimized for mobile devices.
Downloads: 888 / 158678550. Delta: 0.10303 с