//测试

 $cache = new Cache();

 $cache->dir = "../cc/";

 //$cache->setCache("zhang", "zhangsan", 100);

 echo $cache->getCache("zhang");

 //$cache->removeCache("zhang");

 $cache->setCache("liu", "liuqi", 100);

 echo $cache->getCache("liu");

 class Cache{

     public $cacheFile = "cache.json";    //文件

     public $dir = "./cach2/";            //目录

     //缓存

     public function setCache($name, $val, $expires_time){

         $file = $this->hasFile();

         //字符串转数组

         $str = file_get_contents($file);

         $arr = json_decode($str, true);

         //值为空，则移除该缓存

         if(empty($val)){

             unset($arr[$name]);

         }else{

             $arr[$name] = array("value"=>$val, "expires_time"=>$expires_time, "add_time"=>time());

         }

         //数组转字符串

         $str = json_encode($arr);

         file_put_contents($file, $str);

     }

     public function getCache($name){

         $file = $this->hasFile();

         //字符串转数组

         $str = file_get_contents($file);

         $allArr = json_decode($str, true);

         $arr = $allArr[$name];

         if(!$arr || time() > ($arr["expires_time"] + $arr["add_time"])){

             $this->removeCache($name);    //过期移除

             return false;

         }

         return $arr["value"];

     }

     public function removeCache($name){

         $this->setCache($name, '', 0);

     }

     private function hasFile(){

         //如果不存在缓存文件，则创建一个

         if(!file_exists($this->dir)){

             mkdir($this->dir);

         }

         if(!file_exists($this->dir . $this->cacheFile)){

             touch($this->dir . $this->cacheFile);

         }

         return $this->dir . $this->cacheFile;

     }

 }