Getyear is deprecated java
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 United States Naval Observatory (USNO):
- A year y is represented by the integer y — 1900 .
- A month is represented by an integer from 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.
Constructor Summary
Allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date) or GregorianCalendar(year + 1900, month, date) .
As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date, hrs, min) or GregorianCalendar(year + 1900, month, date, hrs, min) .
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 to represent the specified number of milliseconds since the standard base time known as «the epoch», namely January 1, 1970, 00:00:00 GMT.
java.util.Date и getYear ()
Я не понимаю 112 бит, которые, как я думал, были бы 2012 годом. Что происходит? Это java.util.Date класс непригодным для использования? Я храню это как поле в нескольких моих классов для хранения даты и времени. Что мне делать?
9 ответов
@Deprecated public int getYear() Устаревшие. Начиная с версии JDK версии 1.1, заменяется на Calendar.get(Calendar.YEAR) — 1900 . Возвращает значение, которое является результатом вычитания 1900 из года, который содержит или начинается с момента времени, представленного этим объектом Date, как интерпретируется в локальном часовом поясе. Возврат: год, представленный этой датой, минус 1900 г. См. также: Calendar Итак, 112 — правильный вывод. Я буду следовать советам в Javadoc или использовать JodaTime вместо этого.
@jumpnett — нет, это совсем не ошибка, она работает точно так, как и должна. Он возвращает смещение текущего года на 1900 год. Почему кто-то в Sun подумал, что это хорошая идея, это совершенно другой вопрос.
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = format.parse(datetime); SimpleDateFormat df = new SimpleDateFormat("yyyy"); year = df.format(date); В дополнение ко всем комментариям, я думал, что могу добавить код о том, как использовать java.util.Date, java.util.Calendar и java.util.GregorianCalendar в соответствии с Javadoc.
//Initialize your Date however you like it. Date date = new Date(); Calendar calendar = new GregorianCalendar(); calendar.setTime(date); int year = calendar.get(Calendar.YEAR); //Add one to month int month = calendar.get(Calendar.MONTH) + 1; int day = calendar.get(Calendar.DAY_OF_MONTH); Не используйте Date , используйте Calendar :
// Beware: months are zero-based and no out of range errors are reported Calendar date = new GregorianCalendar(2012, 9, 5); int year = date.get(Calendar.YEAR); // 2012 int month = date.get(Calendar.MONTH); // 9 - October. int day = date.get(Calendar.DAY_OF_MONTH); // 5 Он также поддерживает время:
Calendar dateTime = new GregorianCalendar(2012, 3, 4, 15, 16, 17); int hour = dateTime.get(Calendar.HOUR_OF_DAY); // 15 int minute = dateTime.get(Calendar.MINUTE); // 16 int second = dateTime.get(Calendar.SECOND); // 17 Да, это на самом деле то, что происходит. См. Также Javadoc:
Returns: the year represented by this date, minus 1900. Метод getYear устарел по этой причине. Поэтому не используйте его.
Обратите внимание также, что getMonth возвращает число от 0 до 11. Следовательно, this.sale.getSaleDate().getMonth() возвращает 1 для февраля, а не 2. Пока java.util.Calendar не добавляет 1900 к годам, он страдает от off-by -немесячная проблема.
Вам гораздо лучше использовать JodaTime.
java.time
Оба класса java.util.Date и java.util.Calendar являются устаревшими, теперь вытесняются инфраструктурой java.time, встроенной в Java 8 и более поздние версии. Большая часть функциональности java.time была перенесена на Java 6 и 7, а также адаптирована для Android.
Часовой пояс имеет решающее значение для определения даты. В любой данный момент дата может изменяться по всему миру по часовому поясу.
Если вы хотите только дату без времени суток, используйте LocalDate . В этом классе отсутствует информация о часовом поясе, но вы можете указать часовой пояс для определения текущей даты.
ZoneId zoneId = ZoneId.of( "America/Montreal" ); LocalDate localDate = LocalDate.now( zoneId ); Вы можете получить различные фрагменты информации с помощью getYear , getMonth и getDayOfMonth . Фактически вы получите номер года с java.time!
int year = localDate.getYear(); Если вам нужна дата-время, а не только дата, используйте класс ZonedDateTime .
Class Date
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 United States Naval Observatory (USNO):
and the material regarding «Systems of Time» at:
which has descriptions of various different time systems including UT, UT1, and UTC.
- A year y is represented by the integer y — 1900 .
- A month is represented by an integer from 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.
Constructor Summary
Allocates a Date object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date) or GregorianCalendar(year + 1900, month, date) .
As of JDK version 1.1, replaced by Calendar.set(year + 1900, month, date, hrs, min) or GregorianCalendar(year + 1900, month, date, hrs, min) .
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 to represent the specified number of milliseconds since the standard base time known as «the epoch», namely January 1, 1970, 00:00:00 GMT.