获取自Java中的Epoch以来的天数,周数和月数

Question

我试图获得自Java中Epoch以来的天数,周数,月数.

Java Calendar类提供了诸如calendar.get(GregorianCalendar.DAY_OF_YEAR)或Calendar.get(GregorianCalendar.WEEK_OF_YEAR)之类的东西,这是一个很好的开始,但它并不能完全满足我的需要.

在Java中有一种优雅的方法吗？

Answer 1

您可以使用Joda Time库轻松完成此操作 - 除了使用标准的Java Date和Calendar类之外,我还可以将它用于任何相关的时间.使用库查看下面的示例:

MutableDateTime epoch = new MutableDateTime();
epoch.setDate(0); //Set to Epoch time
DateTime now = new DateTime();

Days days = Days.daysBetween(epoch, now);
Weeks weeks = Weeks.weeksBetween(epoch, now);
Months months = Months.monthsBetween(epoch, now);

System.out.println("Days Since Epoch: " + days.getDays());
System.out.println("Weeks Since Epoch: " + weeks.getWeeks());
System.out.println("Months Since Epoch: " + months.getMonths());

当我运行它时,我得到以下输出:

Days Since Epoch: 15122
Weeks Since Epoch: 2160
Months Since Epoch: 496

Answer 2

java.time

使用Java 8及更高版本中内置的java.time类.

LocalDate now = LocalDate.now();
LocalDate epoch = LocalDate.ofEpochDay(0);

System.out.println("Days: " + ChronoUnit.DAYS.between(epoch, now));
System.out.println("Weeks: " + ChronoUnit.WEEKS.between(epoch, now));
System.out.println("Months: " + ChronoUnit.MONTHS.between(epoch, now));

产量

Days: 16857
Weeks: 2408
Months: 553

Answer 3

我有点惊讶，几乎所有的答案实际上都在计算epoch和之间的天数now。随着java.time.LocalDate它的那样简单：

LocalDate.now().toEpochDay()

Answer 4

Long currentMilli = System.currentTimeMillis();
Long seconds = currentMilli / 1000;
Long minutes = seconds / 60;
Long hours = minutes / 60;
Long days = hours / 24;
System.out.println("Days since epoch : "  + days);

要么

System.out.println("Days since epoch : "  + ((int) currentMilli / 86400000));