The class Date represents a specific instant
in time, with millisecond precision.
Prior to JDK 1.1, the class Date had two additional
functions. It allowed the interpretation of dates as year, month, day, hour,
minute, and second values. It also allowed the formatting and parsing
of date strings. Unfortunately, the API for these functions was not
amenable to internationalization. As of JDK 1.1, the
Calendar class should be used to convert between dates and time
fields and the DateFormat class should be used to format and
parse date strings.
The corresponding methods in Date are deprecated.
Although the Date class is intended to reflect
coordinated universal time (UTC), it may not do so exactly,
depending on the host environment of the Java Virtual Machine.
Nearly all modern operating systems assume that 1 day =
24 × 60 × 60 = 86400 seconds
in all cases. In UTC, however, about once every year or two there
is an extra second, called a "leap second." The leap
second is always added as the last second of the day, and always
on December 31 or June 30. For example, the last minute of the
year 1995 was 61 seconds long, thanks to an added leap second.
Most computer clocks are not accurate enough to be able to reflect
the leap-second distinction.
Some computer standards are defined in terms of Greenwich mean
time (GMT), which is equivalent to universal time (UT). GMT is
the "civil" name for the standard; UT is the
"scientific" name for the same standard. The
distinction between UTC and UT is that UTC is based on an atomic
clock and UT is based on astronomical observations, which for all
practical purposes is an invisibly fine hair to split. Because the
earth's rotation is not uniform (it slows down and speeds up
in complicated ways), UT does not always flow uniformly. Leap
seconds are introduced as needed into UTC so as to keep UTC within
0.9 seconds of UT1, which is a version of UT with certain
corrections applied. There are other time and date systems as
well; for example, the time scale used by the satellite-based
global positioning system (GPS) is synchronized to UTC but is
not adjusted for leap seconds. An interesting source of
further information is the U.S. Naval Observatory, particularly
the Directorate of Time at:
In all methods of class Date that accept or return
year, month, date, hours, minutes, and seconds values, the
following representations are used:
A year y is represented by the integer
y- 1900.
A month is represented by an integer form 0 to 11; 0 is January,
1 is February, and so forth; thus 11 is December.
A date (day of month) is represented by an integer from 1 to 31
in the usual manner.
An hour is represented by an integer from 0 to 23. Thus, the hour
from midnight to 1 a.m. is hour 0, and the hour from noon to 1
p.m. is hour 12.
A minute is represented by an integer from 0 to 59 in the usual manner.
A second is represented by an integer from 0 to 61; the values 60 and
61 occur only for leap seconds and even then only in Java
implementations that actually track leap seconds correctly. Because
of the manner in which leap seconds are currently introduced, it is
extremely unlikely that two leap seconds will occur in the same
minute, but this specification follows the date and time conventions
for ISO C.
In all cases, arguments given to methods for these purposes need
not fall within the indicated ranges; for example, a date may be
specified as January 32 and is interpreted as meaning February 1.
Date()
Allocates a Date object and initializes it so that
it represents the time at which it was allocated, measured to the
nearest millisecond.
Date(int year,
int month,
int date) Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date)
or GregorianCalendar(year + 1900, month, date).
Date(int year,
int month,
int date,
int hrs,
int min) Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min) or GregorianCalendar(year + 1900,
month, date, hrs, min).
Date(int year,
int month,
int date,
int hrs,
int min,
int sec) Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min, sec) or GregorianCalendar(year + 1900,
month, date, hrs, min, sec).
Date(long date)
Allocates a Date object and initializes it to
represent the specified number of milliseconds since the
standard base time known as "the epoch", namely January 1,
1970, 00:00:00 GMT.
Date(String s) Deprecated.As of JDK version 1.1,
replaced by DateFormat.parse(String s).
Method Summary
boolean
after(Date when)
Tests if this date is after the specified date.
boolean
before(Date when)
Tests if this date is before the specified date.
toString()
Converts this Date object to a String
of the form:
static long
UTC(int year,
int month,
int date,
int hrs,
int min,
int sec) Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min, sec) or GregorianCalendar(year + 1900,
month, date, hrs, min, sec), using a UTC
TimeZone, followed by Calendar.getTime().getTime().
Allocates a Date object and initializes it to
represent the specified number of milliseconds since the
standard base time known as "the epoch", namely January 1,
1970, 00:00:00 GMT.
Parameters:
date - the milliseconds since January 1, 1970, 00:00:00 GMT.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date)
or GregorianCalendar(year + 1900, month, date).
Allocates a Date object and initializes it so that
it represents midnight, local time, at the beginning of the day
specified by the year, month, and
date arguments.
public Date(int year,
int month,
int date,
int hrs,
int min)
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min) or GregorianCalendar(year + 1900,
month, date, hrs, min).
Allocates a Date object and initializes it so that
it represents the instant at the start of the minute specified by
the year, month, date,
hrs, and min arguments, in the local
time zone.
public Date(int year,
int month,
int date,
int hrs,
int min,
int sec)
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min, sec) or GregorianCalendar(year + 1900,
month, date, hrs, min, sec).
Allocates a Date object and initializes it so that
it represents the instant at the start of the second specified
by the year, month, date,
hrs, min, and sec arguments,
in the local time zone.
Deprecated.As of JDK version 1.1,
replaced by DateFormat.parse(String s).
Allocates a Date object and initializes it so that
it represents the date and time indicated by the string
s, which is interpreted as if by the
parse(java.lang.String) method.
CloneNotSupportedException - if the object's class does not
support the Cloneable interface. Subclasses
that override the clone method can also
throw this exception to indicate that an instance cannot
be cloned.
public static long UTC(int year,
int month,
int date,
int hrs,
int min,
int sec)
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(year + 1900, month, date,
hrs, min, sec) or GregorianCalendar(year + 1900,
month, date, hrs, min, sec), using a UTC
TimeZone, followed by Calendar.getTime().getTime().
Determines the date and time based on the arguments. The
arguments are interpreted as a year, month, day of the month,
hour of the day, minute within the hour, and second within the
minute, exactly as for the Date constructor with six
arguments, except that the arguments are interpreted relative
to UTC rather than to the local time zone. The time indecated is
returned represented as the distance, measured in milliseconds,
of that time from the epoch (00:00:00 GMT on January 1, 1970).
Parameters:
year - the year minus 1900.
month - the month between 0-11.
date - the day of the month between 1-31.
hrs - the hours between 0-23.
min - the minutes between 0-59.
sec - the seconds between 0-59.
Returns:
the number of milliseconds since January 1, 1970, 00:00:00 GMT for
the date and time specified by the arguments.
Deprecated.As of JDK version 1.1,
replaced by DateFormat.parse(String s).
Attempts to interpret the string s as a representation
of a date and time. If the attempt is successful, the time
indicated is returned represented as the distance, measured in
milliseconds, of that time from the epoch (00:00:00 GMT on
January 1, 1970). If the attempt fails, an
IllegalArgumentException is thrown.
It accepts many syntaxes; in particular, it recognizes the IETF
standard date syntax: "Sat, 12 Aug 1995 13:30:00 GMT". It also
understands the continental U.S. time-zone abbreviations, but for
general use, a time-zone offset should be used: "Sat, 12 Aug 1995
13:30:00 GMT+0430" (4 hours, 30 minutes west of the Greenwich
meridian). If no time zone is specified, the local time zone is
assumed. GMT and UTC are considered equivalent.
The string s is processed from left to right, looking for
data of interest. Any material in s that is within the
ASCII parenthesis characters ( and ) is ignored.
Parentheses may be nested. Otherwise, the only characters permitted
within s are these ASCII characters:
A consecutive sequence of decimal digits is treated as a decimal
number:
If a number is preceded by + or - and a year
has already been recognized, then the number is a time-zone
offset. If the number is less than 24, it is an offset measured
in hours. Otherwise, it is regarded as an offset in minutes,
expressed in 24-hour time format without punctuation. A
preceding - means a westward offset. Time zone offsets
are always relative to UTC (Greenwich). Thus, for example,
-5 occurring in the string would mean "five hours west
of Greenwich" and +0430 would mean "four hours and
thirty minutes east of Greenwich." It is permitted for the
string to specify GMT, UT, or UTC
redundantly-for example, GMT-5 or utc+0430.
The number is regarded as a year number if one of the
following conditions is true:
The number is equal to or greater than 70 and followed by a
space, comma, slash, or end of string
The number is less than 70, and both a month and a day of
the month have already been recognized
If the recognized year number is less than 100, it is
interpreted as an abbreviated year relative to a century of
which dates are within 80 years before and 19 years after
the time when the Date class is initialized.
After adjusting the year number, 1900 is subtracted from
it. For example, if the current year is 1999 then years in
the range 19 to 99 are assumed to mean 1919 to 1999, while
years from 0 to 18 are assumed to mean 2000 to 2018. Note
that this is slightly different from the interpretation of
years less than 100 that is used in SimpleDateFormat.
If the number is followed by a colon, it is regarded as an hour,
unless an hour has already been recognized, in which case it is
regarded as a minute.
If the number is followed by a slash, it is regarded as a month
(it is decreased by 1 to produce a number in the range 0
to 11), unless a month has already been recognized, in
which case it is regarded as a day of the month.
If the number is followed by whitespace, a comma, a hyphen, or
end of string, then if an hour has been recognized but not a
minute, it is regarded as a minute; otherwise, if a minute has
been recognized but not a second, it is regarded as a second;
otherwise, it is regarded as a day of the month.
A consecutive sequence of letters is regarded as a word and treated
as follows:
A word that matches AM, ignoring case, is ignored (but
the parse fails if an hour has not been recognized or is less
than 1 or greater than 12).
A word that matches PM, ignoring case, adds 12
to the hour (but the parse fails if an hour has not been
recognized or is less than 1 or greater than 12).
Any word that matches any prefix of SUNDAY, MONDAY, TUESDAY,
WEDNESDAY, THURSDAY, FRIDAY, or SATURDAY, ignoring
case, is ignored. For example, sat, Friday, TUE, and
Thurs are ignored.
Otherwise, any word that matches any prefix of JANUARY,
FEBRUARY, MARCH, APRIL, MAY, JUNE, JULY, AUGUST, SEPTEMBER,
OCTOBER, NOVEMBER, or DECEMBER, ignoring case, and
considering them in the order given here, is recognized as
specifying a month and is converted to a number (0 to
11). For example, aug, Sept, april, and
NOV are recognized as months. So is Ma, which
is recognized as MARCH, not MAY.
Any word that matches GMT, UT, or UTC, ignoring
case, is treated as referring to UTC.
Any word that matches EST, CST, MST, or PST,
ignoring case, is recognized as referring to the time zone in
North America that is five, six, seven, or eight hours west of
Greenwich, respectively. Any word that matches EDT, CDT,
MDT, or PDT, ignoring case, is recognized as
referring to the same time zone, respectively, during daylight
saving time.
Once the entire string s has been scanned, it is converted to a time
result in one of two ways. If a time zone or time-zone offset has been
recognized, then the year, month, day of month, hour, minute, and
second are interpreted in UTC and then the time-zone offset is
applied. Otherwise, the year, month, day of month, hour, minute, and
second are interpreted in the local time zone.
Parameters:
s - a string to be parsed as a date.
Returns:
the number of milliseconds since January 1, 1970, 00:00:00 GMT
represented by the string argument.
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.YEAR) - 1900.
Returns a value that is the result of subtracting 1900 from the
year that contains or begins with the instant in time represented
by this Date object, as interpreted in the local
time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.YEAR, year + 1900).
Sets the year of this Date object to be the specified
value plus 1900. This Date object is modified so
that it represents a point in time within the specified year,
with the month, date, hour, minute, and second the same as
before, as interpreted in the local time zone. (Of course, if
the date was February 29, for example, and the year is set to a
non-leap year, then the new date will be treated as if it were
on March 1.)
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.MONTH).
Returns a number representing the month that contains or begins
with the instant in time represented by this Date object.
The value returned is between 0 and 11,
with the value 0 representing January.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.MONTH, int month).
Sets the month of this date to the specified value. This
Date object is modified so that it represents a point
in time within the specified month, with the year, date, hour,
minute, and second the same as before, as interpreted in the
local time zone. If the date was October 31, for example, and
the month is set to June, then the new date will be treated as
if it were on July 1, because June has only 30 days.
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.DAY_OF_MONTH).
Returns the day of the month represented by this Date object.
The value returned is between 1 and 31
representing the day of the month that contains or begins with the
instant in time represented by this Date object, as
interpreted in the local time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.DAY_OF_MONTH, int date).
Sets the day of the month of this Date object to the
specified value. This Date object is modified so that
it represents a point in time within the specified day of the
month, with the year, month, hour, minute, and second the same
as before, as interpreted in the local time zone. If the date
was April 30, for example, and the date is set to 31, then it
will be treated as if it were on May 1, because April has only
30 days.
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.DAY_OF_WEEK).
Returns the day of the week represented by this date. The
returned value (0 = Sunday, 1 = Monday,
2 = Tuesday, 3 = Wednesday, 4 =
Thursday, 5 = Friday, 6 = Saturday)
represents the day of the week that contains or begins with
the instant in time represented by this Date object,
as interpreted in the local time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.HOUR_OF_DAY).
Returns the hour represented by this Date object. The
returned value is a number (0 through 23)
representing the hour within the day that contains or begins
with the instant in time represented by this Date
object, as interpreted in the local time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.HOUR_OF_DAY, int hours).
Sets the hour of this Date object to the specified value.
This Date object is modified so that it represents a point
in time within the specified hour of the day, with the year, month,
date, minute, and second the same as before, as interpreted in the
local time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.MINUTE, int minutes).
Sets the minutes of this Date object to the specified value.
This Date object is modified so that it represents a point
in time within the specified minute of the hour, with the year, month,
date, hour, and second the same as before, as interpreted in the
local time zone.
Deprecated.As of JDK version 1.1,
replaced by Calendar.get(Calendar.SECOND).
Returns the number of seconds past the minute represented by this date.
The value returned is between 0 and 61. The
values 60 and 61 can only occur on those
Java Virtual Machines that take leap seconds into account.
Returns:
the number of seconds past the minute represented by this date.
Deprecated.As of JDK version 1.1,
replaced by Calendar.set(Calendar.SECOND, int seconds).
Sets the seconds of this Date to the specified value.
This Date object is modified so that it represents a
point in time within the specified second of the minute, with
the year, month, date, hour, and minute the same as before, as
interpreted in the local time zone.
Compares two dates for equality.
The result is true if and only if the argument is
not null and is a Date object that
represents the same point in time, to the millisecond, as this object.
Thus, two Date objects are equal if and only if the
getTime method returns the same long
value for both.
the value 0 if the argument Date is equal to
this Date; a value less than 0 if this Date
is before the Date argument; and a value greater than
0 if this Date is after the Date argument.
Compares this Date to another Object. If the Object is a Date,
this function behaves like compareTo(Date). Otherwise,
it throws a ClassCastException (as Dates are comparable
only to other Dates).
the value 0 if the argument is a Date
equal to this Date; a value less than 0 if the
argument is a Date after this Date; and a value greater than
0 if the argument is a Date before this Date.
Returns a hash code value for this object. The result is the
exclusive OR of the two halves of the primitive long
value returned by the getTime()
method. That is, the hash code is the value of the expression:
Converts this Date object to a String
of the form:
dow mon dd hh:mm:ss zzz yyyy
where:
dow is the day of the week (Sun, Mon, Tue, Wed,
Thu, Fri, Sat).
mon is the month (Jan, Feb, Mar, Apr, May, Jun,
Jul, Aug, Sep, Oct, Nov, Dec).
dd is the day of the month (01 through
31), as two decimal digits.
hh is the hour of the day (00 through
23), as two decimal digits.
mm is the minute within the hour (00 through
59), as two decimal digits.
ss is the second within the minute (00 through
61, as two decimal digits.
zzz is the time zone (and may reflect daylight savings
time). Standard time zone abbreviations include those
recognized by the method parse. If time zone
informationi is not available, then zzz is empty -
that is, it consists of no characters at all.
Deprecated.As of JDK version 1.1,
replaced by DateFormat.format(Date date).
Creates a string representation of this Date object in an
implementation-dependent form. The intent is that the form should
be familiar to the user of the Java application, wherever it may
happen to be running. The intent is comparable to that of the
"%c" format supported by the strftime()
function of ISO C.
Returns:
a string representation of this date, using the locale
conventions.
Submit a bug or feature For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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