// a integer to xx:xx:xx     public static String secToTime(int time) {         String timeStr = null;         int hour = 0;         int minute = 0;         int second = 0;         if (time <= 0)             return "00:00";         else {             minute = time / 60;             if (minute < 60) {                 second = time % 60;                 timeStr = unitFormat(minute) + ":" + unitFormat(second);             } else {                 hour = minute / 60;                 if (hour > 99)                     return "99:59:59";                 minute = minute % 60;                 second = time - hour * 3600 - minute * 60;                 timeStr = unitFormat(hour) + ":" + unitFormat(minute) + ":" + unitFormat(second);             }         }         return timeStr;     }     public static String unitFormat(int i) {         String retStr = null;         if (i >= 0 && i < 10)             retStr = "0" + Integer.toString(i);         else             retStr = "" + i;         return retStr;     }