Java 8 LocalDate - 如何获取两个日期之间的所有日期？

Question

是否可以在新的 java.time API 中获取两个日期之间的所有日期？

假设我有这部分代码:

@Test
public void testGenerateChartCalendarData() {
    LocalDate startDate = LocalDate.now();

    LocalDate endDate = startDate.plusMonths(1);
    endDate = endDate.withDayOfMonth(endDate.lengthOfMonth());
}

现在我需要 startDate 和 endDate 之间的所有日期。

我正在考虑获取两个日期的 daysBetween 并迭代:

long daysBetween = ChronoUnit.DAYS.between(startDate, endDate);

for(int i = 0; i <= daysBetween; i++){
    startDate.plusDays(i); //...do the stuff with the new date...
}

有没有更好的方法来获取日期？

Answer 1

假设您主要想迭代日期范围，创建一个可迭代的 DateRange 类是有意义的。这将允许你写:

for (LocalDate d : DateRange.between(startDate, endDate)) ...

类似:

public class DateRange implements Iterable<LocalDate> {

  private final LocalDate startDate;
  private final LocalDate endDate;

  public DateRange(LocalDate startDate, LocalDate endDate) {
    //check that range is valid (null, start < end)
    this.startDate = startDate;
    this.endDate = endDate;
  }

  @Override
  public Iterator<LocalDate> iterator() {
    return stream().iterator();
  }

  public Stream<LocalDate> stream() {
    return Stream.iterate(startDate, d -> d.plusDays(1))
                 .limit(ChronoUnit.DAYS.between(startDate, endDate) + 1);
  }

  public List<LocalDate> toList() { //could also be built from the stream() method
    List<LocalDate> dates = new ArrayList<> ();
    for (LocalDate d = startDate; !d.isAfter(endDate); d = d.plusDays(1)) {
      dates.add(d);
    }
    return dates;
  }
}

添加 equals 和 hashcode 方法、getter 是有意义的，也许有一个静态工厂 + 私有(private)构造函数来匹配 Java 时间 API 等的编码风格。