问题描述
我正在尝试获取特定期间的每月重复日期。除了我指定的重复日期为30以外,下面的代码有效,然后生成以下错误,这是正常的:
线程“ main”中的异常java.time.DateTimeException:无效的日期“ FEBRUARY 30”
我的问题是:如果指定的重复日期(天)高于该月的最后一天,是否可以将重复周期设置为该月的最后一天?
谢谢!
public class MonthlyRecurrence {
public static void main(String[] args) {
LocalDate startDate = LocalDate.of(2020,10,6);
LocalDate endDate = LocalDate.of(2021,12,31);
int dayOfMonth = 30;
List<LocalDate> reportDates = getReportDates(startDate,endDate,dayOfMonth);
System.out.println(reportDates);
}
private static List<LocalDate> getReportDates(LocalDate startDate,LocalDate endDate,int dayOfMonth) {
List<LocalDate> dates = new ArrayList<>();
LocalDate reportDate = startDate;
while (reportDate.isBefore(endDate)) {
reportDate = reportDate.plusMonths(1).withDayOfMonth(dayOfMonth);
dates.add(reportDate);
}
return dates;
}
}
解决方法
您需要指定TemporalAdjuster来获取每月的特定日期,而与月份的长度无关。它作为第三个参数传递给您的方法。
因为我不确定您想要什么,所以我包括了两个调节器。一个月的特定日期,一个月的最后一天。它们可以互换使用。但是,后者不会到达Dec 31,2021
,因为before
排除了==
LocalDate startDate = LocalDate.of(2020,10,6);
LocalDate endDate = LocalDate.of(2021,12,31);
// Adjuster for a specific day
int dayOfMonth = 30; // must be final or effectively final
// as it is used in the following lambda.
TemporalAdjuster specificDay =
date-> {
LocalDate ld = (LocalDate)date;
int max = ld.getMonth().length(ld.isLeapYear());
int day = dayOfMonth > max ? max : dayOfMonth;
return date.with(ChronoField.DAY_OF_MONTH,day);
};
// Adjuster for the lastDay of the month.
TemporalAdjuster lastDay = TemporalAdjusters.lastDayOfMonth();
List<LocalDate> reportDates =
getReportDates(startDate,endDate,specificDay);
reportDates.forEach(System.out::println);
private static List<LocalDate> getReportDates(LocalDate startDate,LocalDate endDate,TemporalAdjuster specificDay) {
List<LocalDate> dates = new ArrayList<>();
// round up start day to specificDay
LocalDate reportDate = startDate.with(specificDay);
while (reportDate.isBefore(endDate)) {
dates.add(reportDate);
reportDate = reportDate.plusMonths(1).with(specificDay);
}
return dates;
}
根据TemporalAdjuster
的选择打印以下内容
SpecificDay (30th) LastDayOfMonth
2020-10-30 2020-10-31
2020-11-30 2020-11-30
2020-12-30 2020-12-31
2021-01-30 2021-01-31
2021-02-28 2021-02-28
2021-03-30 2021-03-31
2021-04-30 2021-04-30
2021-05-30 2021-05-31
2021-06-30 2021-06-30
2021-07-30 2021-07-31
2021-08-30 2021-08-31
2021-09-30 2021-09-30
2021-10-30 2021-10-31
2021-11-30 2021-11-30
2021-12-30