是否可以将java中的日期范围拆分为周？

mo49yndu  于 2021-06-27  发布在  Java
关注(0)|答案(2)|浏览(341)

我的问题如下：我有一个daterange（在java中），由2指定 Calendar 对象，一个开始，一个结束。现在我想得到这个范围内所有星期的列表。一周应以两周为单位 Calendar 对象，一个用于开始，一个用于结束。同样重要的是，整个日期范围的开始和结束可以在两个不同的月份，甚至两个不同的年份。

JavaDatejava-8Calendardate-range

2条答案

按热度按时间
z9zf31ra

z9zf31ra1#

下面是您的问题的实现，使用新的时间api，阅读localdate，localdatetime，period等。

LocalDate startDate = LocalDate.of(2019, 12, 12).with(DayOfWeek.MONDAY);
        LocalDate endDate = LocalDate.of(2020, 12, 12);

        //number of weeks
        long weekNumber = ChronoUnit.WEEKS.between(startDate, endDate);

        Map<LocalDate, LocalDate> weeks = new LinkedHashMap<>();
        for (int i = 0; i < weekNumber; i++) {
            LocalDate endOfWeek = startDate.plusDays(6);
            weeks.put(startDate, endOfWeek);
            startDate = endOfWeek.plusDays(1);
        }
        for (LocalDate week : weeks.keySet()) {
            LocalDate endOfWeek = weeks.get(week);
            System.out.println("Start of week: " + week + "[" + week.getDayOfWeek() + "]" +
                    " End of week: " + endOfWeek + "[" + endOfWeek.getDayOfWeek() + "]");
        }

它打印：

Start of week: 2020-12-07[MONDAY] End of week: 2020-12-13[SUNDAY]
Start of week: 2020-12-14[MONDAY] End of week: 2020-12-20[SUNDAY]
Start of week: 2020-12-21[MONDAY] End of week: 2020-12-27[SUNDAY]
Start of week: 2020-12-28[MONDAY] End of week: 2021-01-03[SUNDAY]
Start of week: 2021-01-04[MONDAY] End of week: 2021-01-10[SUNDAY]

等。。。
编辑：
使用datetimeformatter，日期将更短，日期名称将以您的语言显示：

DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd[EEEE]");
for (LocalDate startOfWeek : weeks.keySet()) {
    LocalDate endOfWeek = weeks.get(startOfWeek);
    System.out.println("Start of week: " + dateTimeFormatter.format(startOfWeek) +
                    " End of week: " + dateTimeFormatter.format(endOfWeek));
    }
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wbrvyc0a

wbrvyc0a2#

和老人一起做 Calendar 对象，你可以像答案的前半部分那样做。要使用Java8中添加的较新的JavaTimeAPI来实现这一点，请参阅答案的后半部分。

使用旧日历api

static List<DateRange> weeksCovering(Calendar start, Calendar end) {
    List<DateRange> result = new ArrayList<>();

    Calendar cal = (Calendar) start.clone();
    cal.clear();
    cal.set(start.get(Calendar.YEAR), start.get(Calendar.MONTH), start.get(Calendar.DATE));
    cal.add(Calendar.DATE, (cal.getFirstDayOfWeek() - cal.get(Calendar.DAY_OF_WEEK) - 7) % 7);
    while (cal.compareTo(end) <= 0) {
        Calendar weekStart = (Calendar) cal.clone();
        cal.add(Calendar.DATE, 6);
        Calendar weekEnd = (Calendar) cal.clone();
        cal.add(Calendar.DATE, 1);
        result.add(new DateRange(weekStart, weekEnd));
    }
    return result;
}
public final class DateRange {
    private final Calendar start;
    private final Calendar end;

    public DateRange(Calendar start, Calendar end) {
        this.start = start;
        this.end = end;
    }

    public Calendar getStart() {
        return (Calendar) this.start.clone();
    }
    public Calendar getEnd() {
        return (Calendar) this.end.clone();
    }

    @Override
    public String toString() {
        SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, MMM d, yyyy");
        return dateFormat.format(this.start.getTime()) + " - " +
               dateFormat.format(this.end.getTime());
    }
}

测试

test(2020,12,13, 2021,2,7, Locale.US);
test(2020,12,13, 2021,2,7, Locale.GERMANY);
static void test(int startYear, int startMonth, int startDay, int endYear, int endMonth, int endDay, Locale locale) {
    Calendar start = Calendar.getInstance(locale);
    Calendar end = Calendar.getInstance(locale);
    start.clear();
    end.clear();
    start.set(startYear, startMonth - 1, startDay);
    end.set(endYear, endMonth - 1, endDay);
    List<DateRange> weeks = weeksCovering(start, end);
    System.out.println(new DateRange(start, end) + ":");
    for (DateRange week : weeks)
        System.out.println("  " + week);
}

输出

Sun, Dec 13, 2020 - Sun, Feb 7, 2021:
  Sun, Dec 13, 2020 - Sat, Dec 19, 2020
  Sun, Dec 20, 2020 - Sat, Dec 26, 2020
  Sun, Dec 27, 2020 - Sat, Jan 2, 2021
  Sun, Jan 3, 2021 - Sat, Jan 9, 2021
  Sun, Jan 10, 2021 - Sat, Jan 16, 2021
  Sun, Jan 17, 2021 - Sat, Jan 23, 2021
  Sun, Jan 24, 2021 - Sat, Jan 30, 2021
  Sun, Jan 31, 2021 - Sat, Feb 6, 2021
  Sun, Feb 7, 2021 - Sat, Feb 13, 2021
Sun, Dec 13, 2020 - Sun, Feb 7, 2021:
  Mon, Dec 7, 2020 - Sun, Dec 13, 2020
  Mon, Dec 14, 2020 - Sun, Dec 20, 2020
  Mon, Dec 21, 2020 - Sun, Dec 27, 2020
  Mon, Dec 28, 2020 - Sun, Jan 3, 2021
  Mon, Jan 4, 2021 - Sun, Jan 10, 2021
  Mon, Jan 11, 2021 - Sun, Jan 17, 2021
  Mon, Jan 18, 2021 - Sun, Jan 24, 2021
  Mon, Jan 25, 2021 - Sun, Jan 31, 2021
  Mon, Feb 1, 2021 - Sun, Feb 7, 2021

注意它如何正确地调整到 Locale 由起始日历对象标识。

使用更新的Java8时间api

static List<DateRange> weeksCovering(LocalDate start, LocalDate end, WeekFields weekFields) {
    List<DateRange> result = new ArrayList<>();

    LocalDate date = start.with(TemporalAdjusters.previousOrSame(weekFields.getFirstDayOfWeek()));
    while (date.compareTo(end) <= 0) {
        LocalDate weekStart = date;
        date = date.plusDays(6);
        LocalDate weekEnd = date;
        date = date.plusDays(1);
        result.add(new DateRange(weekStart, weekEnd));
    }
    return result;
}
public final class DateRange {
    private final LocalDate start;
    private final LocalDate end;

    public DateRange(LocalDate start, LocalDate end) {
        this.start = start;
        this.end = end;
    }

    public LocalDate getStart() {
        return this.start;
    }
    public LocalDate getEnd() {
        return this.end;
    }

    @Override
    public String toString() {
        DateTimeFormatter dateFormat = DateTimeFormatter.ofPattern("EEE, MMM d, uuuu");
        return dateFormat.format(this.start) + " - " + dateFormat.format(this.end);
    }
}

测试

test(2020,12,13, 2021,2,7, Locale.US);
test(2020,12,13, 2021,2,7, Locale.GERMANY);
static void test(int startYear, int startMonth, int startDay, int endYear, int endMonth, int endDay, Locale locale) {
    LocalDate start = LocalDate.of(startYear, startMonth, startDay);
    LocalDate end = LocalDate.of(endYear, endMonth, endDay);
    List<DateRange> weeks = weeksCovering(start, end, WeekFields.of(locale));
    System.out.println(new DateRange(start, end) + ":");
    for (DateRange week : weeks)
        System.out.println("  " + week);
}

输出

Sun, Dec 13, 2020 - Sun, Feb 7, 2021:
  Sun, Dec 13, 2020 - Sat, Dec 19, 2020
  Sun, Dec 20, 2020 - Sat, Dec 26, 2020
  Sun, Dec 27, 2020 - Sat, Jan 2, 2021
  Sun, Jan 3, 2021 - Sat, Jan 9, 2021
  Sun, Jan 10, 2021 - Sat, Jan 16, 2021
  Sun, Jan 17, 2021 - Sat, Jan 23, 2021
  Sun, Jan 24, 2021 - Sat, Jan 30, 2021
  Sun, Jan 31, 2021 - Sat, Feb 6, 2021
  Sun, Feb 7, 2021 - Sat, Feb 13, 2021
Sun, Dec 13, 2020 - Sun, Feb 7, 2021:
  Mon, Dec 7, 2020 - Sun, Dec 13, 2020
  Mon, Dec 14, 2020 - Sun, Dec 20, 2020
  Mon, Dec 21, 2020 - Sun, Dec 27, 2020
  Mon, Dec 28, 2020 - Sun, Jan 3, 2021
  Mon, Jan 4, 2021 - Sun, Jan 10, 2021
  Mon, Jan 11, 2021 - Sun, Jan 17, 2021
  Mon, Jan 18, 2021 - Sun, Jan 24, 2021
  Mon, Jan 25, 2021 - Sun, Jan 31, 2021
  Mon, Feb 1, 2021 - Sun, Feb 7, 2021

注意它如何正确地调整到 Locale 由起始日历对象标识。

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