时间相减得到时分秒

public function secToTime($times){
    $result = '00:00:00';
    if ($times>0) {
        $hour = floor($times/3600);
        $minute = floor(($times-3600 * $hour)/60);
        $second = floor((($times-3600 * $hour) - 60 * $minute) % 60);

        $result = $this->len($hour).':'.$this->len($minute).':'.$this->len($second);
    }
    return $result;
}

public function len($str){
    if(strlen($str) == 1){
        $time = '0'.$str;
    }else{
        $time = $str;
    }
    return $time;
}