获取凌晨时间的方法

public static Date weeHours(Date date, int flag) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int hour = cal.get(Calendar.HOUR_OF_DAY);
        int minute = cal.get(Calendar.MINUTE);
        int second = cal.get(Calendar.SECOND);
        //时分秒（毫秒数）
        long millisecond = hour*60*60*1000 + minute*60*1000 + second*1000;
        System.out.println(cal.getTimeInMillis()-millisecond);
        //凌晨00:00:00
        cal.setTimeInMillis(cal.getTimeInMillis()-millisecond);
         
        if (flag == 0) {
            return cal.getTime();
        } else if (flag == 1) {
            //凌晨23:59:59
            cal.setTimeInMillis(cal.getTimeInMillis()+23*60*60*1000 + 59*60*1000 + 59*1000);
        }
        return cal.getTime();
    }