java 计算多个时间段中重复的天数

    /**
     * 计算多个时间段中的重复时间
     *
     * @param seTimes 按时间段的开始时间排好序的时间段集合
     */
    public static int calcRepetition(List<Map<String, Date>> seTimes) {
        if (CollUtil.isEmpty(seTimes)) {
            return 0;
        }
        //按开始时间排序
        seTimes = seTimes.stream().peek(m -> {
            // 设置时间为当天开始时间
            m.put("st", DateUtil.beginOfDay(m.get("st")));
            m.put("et", DateUtil.beginOfDay(m.get("et")));
        }).sorted(Comparator.comparing(x -> x.get("st"))).collect(Collectors.toList());
        int repetition = 0;
        Date right = seTimes.get(0).get("et");
        for (int i = 0; i < seTimes.size() - 1; i++) {
            Date stn = seTimes.get(i + 1).get("st");
            Date etn = seTimes.get(i + 1).get("et");
            if (right.compareTo(stn) > 0) {
                if (right.compareTo(etn) >= 0) {
                    repetition += DateUtil.betweenDay(stn, etn, true);
                    continue;
                } else if (right.compareTo(etn) < 0) {
                    repetition += DateUtil.betweenDay(stn, right, true);
                }
            }
            right = etn;
        }
        return repetition;
    }1.