PHP 计算Date类型的差值

<?php
class timeDiffer{

function getTimeDiffer($startdate){
$enddate=date('Y-m-d H:i:s',time());
$date=floor((strtotime($enddate)-strtotime($startdate))/86400);
          $hour=floor(((strtotime($enddate)-strtotime($startdate))%86400)/3600%24);
          $minute=floor(((strtotime($enddate)-strtotime($startdate))%86400)/60%60);
          $second=floor((strtotime($enddate)-strtotime($startdate))%86400%60);

$differTime = "";
if((!empty($date))||$date!=null||$date!=0){
$differTime =$differTime.$date."天";
}
if((!empty($hour))||$hour!=null||$hour!=0){
$differTime =$differTime.$hour."小时";
}
if((!empty($minute))||$minute!=null||$minute!=0){
$differTime =$differTime.$minute."分钟";
}
if((!empty($second))||$second!=null||$second!=0){
$differTime =$differTime.$second."分钟";
}

// echo $date."天<br>";
// echo $hour."小时<br>";
// echo $minute."分钟<br>";
// echo $second."秒<br>";

return $differTime;
}
}
?>