java 距离今天/本月结束还有多少秒

/**
 * 获取距离今天结束还有多少秒
 * @return 秒数
 */
public static long getSecondByEndToday() {
    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.DAY_OF_YEAR,1);
    calendar.set(Calendar.HOUR_OF_DAY,0);
    calendar.set(Calendar.SECOND,0);
    calendar.set(Calendar.MINUTE,0);
    calendar.set(Calendar.MILLISECOND,0);
    return ((calendar.getTimeInMillis()-System.currentTimeMillis()) / 1000) ;
}

/**
 * 获取距离本月结束还有多少秒
 * @return 秒数
 */
public static long getSecondByMonthEndDay() {
    LocalDate today = LocalDate.now();
    //本月的最后一天
    LocalDate lastDay = today.with(TemporalAdjusters.lastDayOfMonth());
    Date endTimeInMonth = Date.from(lastDay.atStartOfDay(ZoneOffset.ofHours(8)).toInstant());
    Calendar calendar = Calendar.getInstance();
    if(null != endTimeInMonth ) {calendar.setTime(endTimeInMonth );}
    calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
    calendar.set(Calendar.MILLISECOND, 999);
    Date date = calendar.getTime();
    return ((date.getTime()-System.currentTimeMillis()) / 1000) ;
}