简单的php缓存类分享

<?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 )) {    
            $this->make_dir ( dirname ( $path ) );    
            if (! mkdir ( $path, 0777 ))    
                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);