Java中两个日期之间的周数

Question

我的目的是获取两个日期范围之间的周数。日期 24 日落在第 34 周，第 262018-08-22T12:18:06,166日落在第 35 周。现在的问题是，如果我将其作为开始日期，我将得到 34、35、36。我不期待 36 在这里，因为结束日期不属于第 36 周。任何人都可以帮助我。这个问题与此处提供的解决方案不同，从开始日期到结束日期 Java 的周数。解决方案有一个我最近发现的问题

下面是获取它的代码：

public static void main(String[] args) {

    DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss','SSS");

    LocalDateTime startDate = LocalDateTime.parse("2018-08-24T12:18:06,166", format);

    LocalDateTime endDate = LocalDateTime.parse("2018-08-26T12:19:06,188", format);

    numberOfWeeks(startDate, endDate);

}

public static void numberOfWeeks(LocalDateTime startDate, LocalDateTime endDate) {

    int addWeek = 0;

    TemporalField tf = WeekFields.SUNDAY_START.weekOfYear();

    if (startDate.get(tf) < endDate.get(tf)) {

        addWeek = 1;

    }

    long weeks = WEEKS.between(startDate, endDate) + addWeek;

    List<String> numberWeeks = new ArrayList<>();

    if (weeks >= 0) {

        int week = 0;

        do {

            //Get the number of week

            LocalDateTime dt = startDate.plusWeeks(week);

            int weekNumber = dt.get(tf);

            numberWeeks.add(String.format("%d-W%d", dt.getYear(), weekNumber));

            week++;

        } while (week <= weeks);

    }

    System.out.println(numberWeeks);

}

Answer 1

public static void numberOfWeeks(LocalDateTime startDateTime, LocalDateTime endDateTime) {&nbsp; &nbsp; if (startDateTime.isAfter(endDateTime)) {&nbsp; &nbsp; &nbsp; &nbsp; throw new IllegalArgumentException("End date must not be before start date");&nbsp; &nbsp; }&nbsp; &nbsp; LocalDate endDate = endDateTime.toLocalDate();&nbsp; &nbsp; List<String> numberWeeks = new ArrayList<>();&nbsp; &nbsp; LocalDate currentDate = startDateTime.toLocalDate();&nbsp; &nbsp; while (currentDate.isBefore(endDate)) {&nbsp; &nbsp; &nbsp; &nbsp; numberWeeks.add(formatWeek(currentDate));&nbsp; &nbsp; &nbsp; &nbsp; currentDate = currentDate.plusWeeks(1);&nbsp; &nbsp; }&nbsp; &nbsp; // Now currentDate is on or after endDate, but are they in the same week?&nbsp; &nbsp; if (currentDate.get(WeekFields.SUNDAY_START.weekOfWeekBasedYear())&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; == endDate.get(WeekFields.SUNDAY_START.weekOfWeekBasedYear())) {&nbsp; &nbsp; &nbsp; &nbsp; numberWeeks.add(formatWeek(currentDate));&nbsp; &nbsp; }&nbsp; &nbsp; System.out.println(numberWeeks);}public static String formatWeek(LocalDate currentDate) {&nbsp; &nbsp; return String.format("%d-W%d",&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; currentDate.get(WeekFields.SUNDAY_START.weekBasedYear()),&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; currentDate.get(WeekFields.SUNDAY_START.weekOfWeekBasedYear()));}使用上面的方法，您可以main从问题中打印出方法：[2018-W34、2018-W35]我看到您忽略了链接问题中的另一个答案，即YearWeek来自 ThreeTen Extra 库的答案。所以我假设你不想那样做。所以我使用LocalDate了几个星期。虽然有几个用户未能重现您的确切问题，但我同意您在问题中的代码存在缺陷。

Answer 2

LocalDateTime.parse( "2018-08-24T12:18:06,166".replace( "," , "." ) ).toLocalDate().with( TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY ) ).datesUntil(&nbsp; &nbsp; LocalDateTime.parse( "2018-08-26T12:19:06,188".replace( "," , "." ) ).toLocalDate()&nbsp; &nbsp; .with( TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY ) )&nbsp; &nbsp; .plusWeeks( 1 )&nbsp;&nbsp; &nbsp; ,&nbsp; &nbsp; Period.ofWeeks( 1 )).map( localDate -> localDate.get( WeekFields.SUNDAY_START.weekOfWeekBasedYear() ) ).collect( Collectors.toList() ).toString()[34, 35]流让我们采用 Ole VVWeekFields在正确答案中显示的想法，但使用 Java Stream 技术缩短代码。虽然有趣，但我不一定推荐这种方法。首先解析您的输入字符串以获取LocalDate对象。该LocalDate级表示没有时间一天和不同时区的日期，唯一的价值。不幸的是，java.time类不支持逗号作为小数秒分隔符，而是期望一个句点（FULL STOP）。这与ISO 8601标准相反，该标准允许并且实际上更喜欢逗号。这是我在其他优秀的java.time类中发现的少数缺陷之一，大概是由于来自美国的程序员的偏见。为了解决这个缺陷，我们用一个 FULL STOP 代替逗号。LocalDate inputDateStart =&nbsp;&nbsp; &nbsp; LocalDateTime.parse(&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; "2018-08-24T12:18:06,166".replace( "," , "." )&nbsp; // Unfortunately, the *java.time* classes fail to support the comma and instead only period. This runs contrary to the ISO 8601 standard which allows both and prefers comma.&nbsp; &nbsp; )&nbsp; &nbsp; .toLocalDate();&nbsp;&nbsp;LocalDate inputDateStop =&nbsp;&nbsp; &nbsp; LocalDateTime.parse(&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; "2018-08-26T12:19:06,188".replace( "," , "." )&nbsp;&nbsp; &nbsp; )&nbsp; &nbsp; .toLocalDate();您希望使用定义为从星期日开始的周。因此，将您输入的日期调整为该日期当天或之前的星期日。请注意，我们在此处添加了一个星期以适应问题的需要。更常见的是，我们不会做这个加法，遵循半开方法来定义一个时间跨度，其中开始是包含而结束是不包括的。与半开放相反，问题显然需要完全封闭的方法，其中开头和结尾都包含在内（我不建议这样做）。LocalDate start = inputDateStart.with(&nbsp;&nbsp; &nbsp; TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY )&nbsp;);LocalDate stop = inputDateStop.with(&nbsp;&nbsp; &nbsp; TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY )&nbsp;).plusWeeks( 1 )&nbsp; // Add one to suit the Question, whereas commonly in date-time work we would have used Half-Open logic.;&nbsp;&nbsp;将一系列日期定义为Stream< LocalDate >. 我们通过一周的 a 一次跳跃Period一周。Stream< LocalDate > stream =&nbsp;&nbsp; &nbsp; startDate&nbsp; &nbsp; .datesUntil(&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; stopDate ,&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; Period.ofWeeks( 1 )&nbsp;&nbsp; &nbsp; );如果需要，您可以通过将这些日期从流中收集到列表中来查看这些日期。但请注意，这会耗尽流。您需要重新建立流以继续我们的代码。List< LocalDate > dates = stream.collect( Collectors.toList() );System.out.println( dates );[2018-08-19, 2018-08-26]在流中运行该系列日期。在每个LocalDate对象上，获取周数。收集每个返回的周数作为一个Integer对象，所有收集在一个List.List< Integer > weekNumbers =&nbsp;&nbsp; &nbsp; stream&nbsp; &nbsp; .map(&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; localDate -> localDate.get( WeekFields.SUNDAY_START.weekOfWeekBasedYear() )&nbsp;&nbsp; &nbsp; )&nbsp; &nbsp; .collect( Collectors.toList() );转储到控制台。System.out.println( weekNumbers );[34, 35]单线如果你真的想为简洁而疯狂，我们可以在一行代码中完成所有这些。我不推荐这个，但尝试很有趣。System.out.println(&nbsp; &nbsp; LocalDateTime.parse( "2018-08-24T12:18:06,166".replace( "," , "." ) ).toLocalDate()&nbsp; &nbsp; .with( TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY ) )&nbsp; &nbsp; .datesUntil(&nbsp; &nbsp; &nbsp; &nbsp; LocalDateTime.parse( "2018-08-26T12:19:06,188".replace( "," , "." ) ).toLocalDate()&nbsp; &nbsp; &nbsp; &nbsp; .with( TemporalAdjusters.previousOrSame( DayOfWeek.SUNDAY ) )&nbsp; &nbsp; &nbsp; &nbsp; .plusWeeks( 1 )&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; ,&nbsp; &nbsp; &nbsp; &nbsp; Period.ofWeeks( 1 )&nbsp; &nbsp; )&nbsp; &nbsp; .map( localDate -> localDate.get( WeekFields.SUNDAY_START.weekOfWeekBasedYear() ) )&nbsp; &nbsp; .collect( Collectors.toList() ));[34, 35]