<?php     /**      * @desc 文件缓存      */     class Cache{         const C_FILE = '/Runtime/';         private $dir = '';         const EXT = '.tpl';         private $filename = '';         public function __construct($dir = ''){             $this->dir = $dir;         }         /**          *    @desc 设置文件缓存          *    @param string $key 文件名          *    @param unkonw $data 缓存数据          *    @param int    $expire 过期时间          */         public function set($key,$data,$expire = 0){             $this->filename =     dirname(__FILE__).self::C_FILE.$this->dir.$key.self::EXT;             if(file_exists($this->filename)){                 $res = $this->get($key);                 if(md5($res) == md5(json_encode($data) ) ){                     return true;                 }             }             if(!is_dir(dirname($this->filename))){                 mkdir(dirname($this->filename),0777);             }             $source = fopen($this->filename,'w+');             fwrite($source,json_encode($data));             fclose($source);         }         /**          *    @desc 获取文件          *  @param string $key 文件名          */         public function get($key){             //$filename = dirname(__FILE__).self::C_FILE.$this->dir.$key.self::EXT;             if(!file_exists($this->filename)){                 return '缓存文件已经不存在';             }else{                 $res = file_get_contents($this->filename);             }             return $res;         }         /**          *    @desc 删除文件          *  @param string $key 文件名          */         public function del($key){             unlink($this->filename);         }     }     $data = array('name'=>'song','age'=>20,'sex'=>'man','favority'=>array('apple','banana'));     $cache = new Cache();     $cache->set('cache',$data);     //$cache->get('cache');     //$cache->del('cache');