Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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JavaTM 2 Platform Standard Edition |
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java.lang.Object | +--java.util.Date
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:
http://tycho.usno.navy.mil
and their definitions of "Systems of Time" at:
http://tycho.usno.navy.mil/systime.html
In all methods of class Date that accept or return
year, month, date, hours, minutes, and seconds values, the
following representations are used:
- 1900.
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.
DateFormat,
Calendar,
TimeZone, Serialized Form| Constructor Summary | |
Date()
Allocates a Date object and initializes it so that
it represents the time at which it was allocated, measured to the
nearest millisecond. |
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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). |
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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. |
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Date(String s)
Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s). |
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| 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. |
Object |
clone()
Return a copy of this object. |
int |
compareTo(Date anotherDate)
Compares two Dates for ordering. |
int |
compareTo(Object o)
Compares this Date to another Object. |
boolean |
equals(Object obj)
Compares two dates for equality. |
int |
getDate()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.DAY_OF_MONTH). |
int |
getDay()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.DAY_OF_WEEK). |
int |
getHours()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.HOUR_OF_DAY). |
int |
getMinutes()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.MINUTE). |
int |
getMonth()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.MONTH). |
int |
getSeconds()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.SECOND). |
long |
getTime()
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Date object. |
int |
getTimezoneOffset()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.ZONE_OFFSET) +
Calendar.get(Calendar.DST_OFFSET). |
int |
getYear()
Deprecated. As of JDK version 1.1, replaced by Calendar.get(Calendar.YEAR) - 1900. |
int |
hashCode()
Returns a hash code value for this object. |
static long |
parse(String s)
Deprecated. As of JDK version 1.1, replaced by DateFormat.parse(String s). |
void |
setDate(int date)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.DAY_OF_MONTH, int date). |
void |
setHours(int hours)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.HOUR_OF_DAY, int hours). |
void |
setMinutes(int minutes)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MINUTE, int minutes). |
void |
setMonth(int month)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.MONTH, int month). |
void |
setSeconds(int seconds)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.SECOND, int seconds). |
void |
setTime(long time)
Sets this Date object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT. |
void |
setYear(int year)
Deprecated. As of JDK version 1.1, replaced by Calendar.set(Calendar.YEAR, year + 1900). |
String |
toGMTString()
Deprecated. As of JDK version 1.1, replaced by DateFormat.format(Date date), using a
GMT TimeZone. |
String |
toLocaleString()
Deprecated. As of JDK version 1.1, replaced by DateFormat.format(Date date). |
String |
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(). |
| Methods inherited from class java.lang.Object |
finalize,
getClass,
notify,
notifyAll,
wait,
wait,
wait |
| Constructor Detail |
public Date()
Date object and initializes it so that
it represents the time at which it was allocated, measured to the
nearest millisecond.System.currentTimeMillis()public Date(long date)
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 - the milliseconds since January 1, 1970, 00:00:00 GMT.System.currentTimeMillis()
public Date(int year,
int month,
int date)
Calendar.set(year + 1900, month, date)
or GregorianCalendar(year + 1900, month, date).
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.year - the year minus 1900.month - the month between 0-11.date - the day of the month between 1-31.Calendar
public Date(int year,
int month,
int date,
int hrs,
int min)
Calendar.set(year + 1900, month, date,
hrs, min) or GregorianCalendar(year + 1900,
month, date, hrs, min).
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.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.Calendar
public Date(int year,
int month,
int date,
int hrs,
int min,
int sec)
Calendar.set(year + 1900, month, date,
hrs, min, sec) or GregorianCalendar(year + 1900,
month, date, hrs, min, sec).
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.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.Calendarpublic Date(String s)
DateFormat.parse(String s).
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.s - a string representation of the date.DateFormat,
parse(java.lang.String)| Method Detail |
public Object clone()
Cloneable interface. Subclasses
that override the clone method can also
throw this exception to indicate that an instance cannot
be cloned.Cloneable
public static long UTC(int year,
int month,
int date,
int hrs,
int min,
int sec)
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().
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.Calendarpublic static long parse(String s)
DateFormat.parse(String s).
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:
and whitespace characters.abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 0123456789,+-:/
A consecutive sequence of decimal digits is treated as a decimal number:
SimpleDateFormat.
A consecutive sequence of letters is regarded as a word and treated as follows:
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.
s - a string to be parsed as a date.DateFormatpublic int getYear()
Calendar.get(Calendar.YEAR) - 1900.
Date object, as interpreted in the local
time zone.Calendarpublic void setYear(int year)
Calendar.set(Calendar.YEAR, year + 1900).
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.)year - the year value.Calendarpublic int getMonth()
Calendar.get(Calendar.MONTH).
0 and 11,
with the value 0 representing January.Calendarpublic void setMonth(int month)
Calendar.set(Calendar.MONTH, int month).
month - the month value between 0-11.Calendarpublic int getDate()
Calendar.get(Calendar.DAY_OF_MONTH).
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.Calendarpublic void setDate(int date)
Calendar.set(Calendar.DAY_OF_MONTH, int date).
date - the day of the month value between 1-31.Calendarpublic int getDay()
Calendar.get(Calendar.DAY_OF_WEEK).
Calendarpublic int getHours()
Calendar.get(Calendar.HOUR_OF_DAY).
Calendarpublic void setHours(int hours)
Calendar.set(Calendar.HOUR_OF_DAY, int hours).
hours - the hour value.Calendarpublic int getMinutes()
Calendar.get(Calendar.MINUTE).
0 and 59.Calendarpublic void setMinutes(int minutes)
Calendar.set(Calendar.MINUTE, int minutes).
minutes - the value of the minutes.Calendarpublic int getSeconds()
Calendar.get(Calendar.SECOND).
0 and 61. The
values 60 and 61 can only occur on those
Java Virtual Machines that take leap seconds into account.Calendarpublic void setSeconds(int seconds)
Calendar.set(Calendar.SECOND, int seconds).
seconds - the seconds value.Calendarpublic long getTime()
public void setTime(long time)
time - the number of milliseconds.public boolean before(Date when)
when - a date.true if and only if the instant of time
represented by this Date object is strictly
earlier than the instant represented by when;
false otherwise.public boolean after(Date when)
when - a date.true if and only if the instant represented
by this Date object is strictly later than the
instant represented by when;
false otherwise.public boolean equals(Object obj)
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.
obj - the object to compare with.true if the objects are the same;
false otherwise.getTime()public int compareTo(Date anotherDate)
anotherDate - the Date to be compared.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.public int compareTo(Object o)
compareTo(Date). Otherwise,
it throws a ClassCastException (as Dates are comparable
only to other Dates).o - the Object to be compared.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.Date.Comparablepublic int hashCode()
getTime()
method. That is, the hash code is the value of the expression:
(int)(this.getTime()^(this.getTime() >>> 32))
public String toString()
Date object to a String
of the form:
where:dow mon dd hh:mm:ss zzz yyyy
toLocaleString(),
toGMTString()public String toLocaleString()
DateFormat.format(Date date).
%c" format supported by the strftime()
function of ISO C.DateFormat,
toString(),
toGMTString()public String toGMTString()
DateFormat.format(Date date), using a
GMT TimeZone.
The result does not depend on the local time zone.
DateFormat,
toString(),
toLocaleString()public int getTimezoneOffset()
Calendar.get(Calendar.ZONE_OFFSET) +
Calendar.get(Calendar.DST_OFFSET).
For example, in Massachusetts, five time zones west of Greenwich:
because on February 14, 1996, standard time (Eastern Standard Time) is in use, which is offset five hours from UTC; but:new Date(96, 1, 14).getTimezoneOffset() returns 300
because on May 1, 1996, daylight savings time (Eastern Daylight Time) is in use, which is offset only four hours from UTC.new Date(96, 5, 1).getTimezoneOffset() returns 240
This method produces teh same result as if it computed:
(this.getTime() - UTC(this.getYear(),
this.getMonth(),
this.getDate(),
this.getHours(),
this.getMinutes(),
this.getSeconds())) / (60 * 1000)
Calendar,
TimeZone
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JavaTM 2 Platform Standard Edition |
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| SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | |||||||||