Package java.text

Class DateFormat

  • Direct Known Subclasses:
    SimpleDateFormat
    public abstract class DateFormat
extends Object
    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 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. 

     {
        @code
        DateFormat df = DateFormat.getDateInstance();
        for (int i = 0; i < myDate.length; ++i) {
                output.println(df.format(myDate[i]) + "; ");
        }
 }
 
     {
        @code
        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:

    • 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.

    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.

    See Also:
    SimpleDateFormat, Calendar, TimeZone

    • Field Detail

      • MEDIUM

        public static final int MEDIUM
        Constant for medium style pattern.
        See Also:
        Constant Field Values

      • DEFAULT

        public static final int DEFAULT
        Constant for default style pattern. Its value is MEDIUM.
        See Also:
        Constant Field Values

      • calendar

        protected Calendar calendar
        The Calendar instance used for calculating the date-time fields and the instant of time. This field is used for both formatting and parsing.

    • Constructor Detail

      • DateFormat

        protected DateFormat()
        Create a new date format.

    • Method Detail

      • format

        public abstract 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.

      • getTimeInstance

        public static final DateFormat getTimeInstance()
        Gets the time formatter with the default formatting style.
        Returns:
        a time formatter.

      • getTimeInstance

        public static final DateFormat getTimeInstance​(int style)
        Gets the time formatter with the given formatting style.
        Parameters:
        style - the given formatting style. For example, SHORT for "h:mm a".
        Returns:
        a time formatter.

      • getDateInstance

        public static final DateFormat getDateInstance()
        Gets the date formatter with the default formatting style.
        Returns:
        a date formatter.

      • getDateInstance

        public static final DateFormat getDateInstance​(int style)
        Gets the date formatter with the given formatting style.
        Parameters:
        style - the given formatting style. For example, SHORT for "M/d/yy".
        Returns:
        a date formatter.

      • getDateTimeInstance

        public static final DateFormat getDateTimeInstance()
        Gets the date/time formatter with the default formatting style.
        Returns:
        a date/time formatter.

      • getDateTimeInstance

        public static final DateFormat getDateTimeInstance​(int dateStyle,
                                                   int timeStyle)
        Gets the date/time formatter with the given date and time formatting styles.
        Parameters:
        dateStyle - the given date formatting style. For example, SHORT for "M/d/yy".
        timeStyle - the given time formatting style. For example, SHORT for "h:mm a".
        Returns:
        a date/time formatter.

      • getInstance

        public static final DateFormat getInstance()
        Get a default date/time formatter that uses the SHORT style for both the date and the time.
        Returns:
        a date/time formatter

      • setCalendar

        public void setCalendar​(Calendar newCalendar)
        Set the calendar to be used by this date format. Initially, the default calendar.
        Parameters:
        newCalendar - the new Calendar to be used by the date format

      • getCalendar

        public Calendar getCalendar()
        Gets the calendar associated with this date/time formatter.
        Returns:
        the calendar associated with this date/time formatter.