php缓存    

<?php  class Cache   {   private $dir = "data/cache/";//定义缓存目录    private $key='c_a_sss'; // 文件名 md5加密 密钥      function set_dir($dirpath)   {    $this->dir=$dirpath;    $this->make_dir($this->dir);   }   function read($key,$minutes=1)   {    $filename=$this->get_filename($key);    if($datas = @file_get_contents($filename))    {      $datas = unserialize($datas);      if(time() - $datas['time'] < $minutes*60)      {       return $datas['data'];      }    }    return false;   }      function write($key,$data)   {      $filename=$this->get_filename($key);    if($handle = fopen($filename,'w+'))    {     $datas = array('data'=>$data,'time'=>time());     flock($handle,LOCK_EX);     $rs = fputs($handle,serialize($datas));     flock($handle,LOCK_UN);     fclose($handle);     if($rs!==false){return true;  }    }    return false;   }   function clear_all()   {    $dir=$this->dir;    $this->del_file($dir);    }       private function get_filename($key)   {    return $this->dir.$key.'_'.md5($key.$this->key);   }   private function make_dir($path)   {    if (! file_exists ( $path ))    {     if (! mkdir ( $path, 0777,true)) die ( '无法创建缓存文件夹' . $path );    }   }   private function del_file($dir)   {     if (is_dir($dir))     {      $dh=opendir($dir);//打开目录 //列出目录中的所有文件并去掉 . 和 ..      while (false !== ( $file = readdir ($dh))) {       if($file!="." && $file!="..") {       $fullpath=$dir."/".$file;        if(!is_dir($fullpath)) {         unlink($fullpath);       } else {         $this->del_file($fullpath);        }       }     }     closedir($dh);     }    }   }    $cache = new cache();    $cache->set_dir('data/cache_dir/');    $data=$cache->read('sys',1);    if(empty($data))    {     $data=array('aa'=>1111,'bb'=>2222,'date'=>date('Y-m-d H:i:s'));     $cache->write('sys',$data);     }    print_r($data);