获取日期的周数（星期三开始的一周）

Question

LocalDate initial = LocalDate.now();
DayOfWeek dayOfWeek = DayOfWeek.WEDNESDAY;
WeekFields weekFields = WeekFields.of(dayOfWeek, 1);
int weekNo = date.get(weekFields.weekOfWeekBasedYear());
System.out.println("Week No"+weekNo);

我在日期 2018-07-29 使用上面的代码。我预计第 30 周，但我得到了 31。

我在这里得到 30 的结果缺少什么？

Answer 1

如果您希望根据 ISO-8601, where current week is week 30 获得输出，则需要遵循以下步骤：

Week number according to the ISO-8601 standard, weeks starting on Monday. The first week of the year is the week that contains that year's first Thursday (='First 4-day week').

这是由WeekFields.ISO实现的。

相反，如果您希望一周从 WEDNESDAY 开始，您只需将 minimalDaysInFirstWeek 从 1 更改为 4（='First 4-day week'):

LocalDate date = LocalDate.now();
WeekFields weekFields = WeekFields.of(DayOfWeek.WEDNESDAY, 4);
int weekNo = date.get(weekFields.weekOfWeekBasedYear());
System.out.println("Week No " + weekNo);

获取日期的周数（星期三开始的一周）

Getting the week number for a date (week starting on Wednesday)

java

week-number

java-8