获取一段时间之间，所有的周

WeekParse.java

public static List<WeekBean> parseNatureWeek(long startMs, long endMs) {
        if (startMs > endMs) {
            return Collections.emptyList();
        }

        Calendar calendar = Calendar.getInstance();
        // end date
        calendar.setTimeInMillis(endMs);
        clearTime(calendar);
        endMs = calendar.getTimeInMillis();
        // config week
        calendar.setFirstDayOfWeek(Calendar.MONDAY);
        calendar.setMinimalDaysInFirstWeek(7);
        // start date week info
        calendar.clear();
        calendar.setTimeInMillis(startMs);
        // move to first day in week
        int days = calendar.get(Calendar.DAY_OF_WEEK) - calendar.getFirstDayOfWeek();
        if (days != 0) {
            if (days < 0) {
                days += 7;
            }
            calendar.add(Calendar.DAY_OF_WEEK, -days);
        }
        clearTime(calendar);
        // not 00:00:00, use 00:01:01
        calendar.set(Calendar.MINUTE, 1);
        calendar.set(Calendar.SECOND, 1);
        // gen weekbean list
        long start;
        long end;
        final List<WeekBean> resultList = new ArrayList<>();
        do {
            start = calendar.getTimeInMillis();
            calendar.add(Calendar.DAY_OF_WEEK, 6);
            end = calendar.getTimeInMillis();

            resultList.add(new WeekBean(start, end));
            // update startMs -> endWeekDate
            clearTime(calendar);
            startMs = calendar.getTimeInMillis();
            //
            if (startMs >= endMs) {
                break;
            }

            calendar.clear();
            calendar.setTimeInMillis(end);
            calendar.add(Calendar.DAY_OF_WEEK, 1); // next monday

        } while (true);
        return resultList;
    }

    private static void clearTime(Calendar calendar) {
        calendar.set(Calendar.HOUR_OF_DAY, 0);
        calendar.set(Calendar.MINUTE, 0);
        calendar.set(Calendar.SECOND, 0);
        calendar.set(Calendar.MILLISECOND, 0);
    }

    private static class WeekBean {
        public static final String FORMAT = "MM月dd日";

        public final long startDateMs;
        public final long endDateMs;

        private String mToString;

        public WeekBean(long startDateMs, long endDateMs) {
            this.startDateMs = startDateMs;
            this.endDateMs = endDateMs;
        }

        @Override
        public String toString() {
            if (mToString == null) {
                mToString = DateTimeUtil.longToDateStr(startDateMs, FORMAT) +
                        " — " +
                        DateTimeUtil.longToDateStr(endDateMs, FORMAT);
            }
            return mToString;
        }
    }