Java判断多个时间段是否重合的方法小结

public class DateRangeStr {
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern="yyyy-MM", timezone = "GMT+8")
    private String startDate;//格式：yyyy-MM-dd
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern="yyyy-MM", timezone = "GMT+8")
    private String endDate;//格式：yyyy-MM-dd
}

//判断多个时间段是否有时间间隔  true无间隔  false有间隔
    public boolean hasNoGaps(List<DateRangeStr> sortedStrRanges) {
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        if (sortedStrRanges == null || sortedStrRanges.size() <= 0) return false;

        if (sortedStrRanges.size() == 1) return true;

        List<DateRange> timePeriods = new ArrayList<>();
        for (DateRangeStr ss : sortedStrRanges) {
            LocalDate startDate = LocalDate.parse(ss.getStartDate(), formatter);
            LocalDate endDate = LocalDate.parse(ss.getEndDate(), formatter);

            DateRange dr = new DateRange();
            dr.setStartDate(startDate);
            dr.setEndDate(endDate);
            timePeriods.add(dr);
        }

        Collections.sort(timePeriods, Comparator.comparing(DateRange::getStartDate));

        LocalDate previousEndDate = timePeriods.get(0).getEndDate();

        for (int i = 1; i < timePeriods.size(); i++) {
            DateRange currentPeriod = timePeriods.get(i);

            if (previousEndDate.isAfter(currentPeriod.getStartDate())) {
                // 当前时间段的开始日期早于上一个时间段的结束日期，存在重叠，这不一定是问题
                // 但我们仍然将当前时间段的结束日期作为新的previousEndDate
                previousEndDate = currentPeriod.getEndDate();
            } else if ((!previousEndDate.isEqual(currentPeriod.getStartDate()) && !previousEndDate.plusDays(1L).isEqual(currentPeriod.getStartDate()))) {
                // 发现了间隔
                return false;
            } else {
                // 相邻时间段之间没有间隔
                previousEndDate = currentPeriod.getEndDate();
            }
        }

        return true; // 所有时间段都已遍历完毕，且没有发现时间间隔
    }

public class TimeInterval {
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern="yyyy-MM", timezone = "GMT+8")
    private String start;
    @JsonFormat(shape = JsonFormat.Shape.STRING, pattern="yyyy-MM", timezone = "GMT+8")
    private String end;
}

private static YearMonth parseYearMonth(String input) {
        try {
            return YearMonth.parse(input, MONTH_FORMATTER);
        } catch (Exception e) {
            throw new IllegalArgumentException("Invalid date format: " + input, e);
        }
    }

    public static boolean overlapsOrContainedInIntervals(List<TimeInterval> intervals, String startDate,String endDate) {
        YearMonth yearMonthAStart = parseYearMonth(startDate);
        YearMonth yearMonthAEnd =  parseYearMonth(endDate);

        for (TimeInterval interval : intervals) {
            YearMonth start = parseYearMonth(interval.getStart());
            YearMonth end = parseYearMonth(interval.getEnd());

            // 检查重叠或包含
            if (!start.isAfter(yearMonthAEnd) && !end.isBefore(yearMonthAStart)) {
                return true;
            }
        }

        return false;
    }