$cache = new Cache(); 
 
//从缓存从读取键值 $key 的数据 
$values = $cache->get($key); 
 
//如果没有缓存数据 
if ($values == false) { 
//insert code here... 
//写入键值 $key 的数据 
$cache->put($key, $values); 
} else { 
//insert code here... 
} 

<?php 
class Cache { 
private $cache_path;//path for the cache 
private $cache_expire;//seconds that the cache expires 
 
//cache constructor, optional expiring time and cache path 
public function Cache($exp_time=3600,$path="cache/"){ 
$this->cache_expire=$exp_time; 
$this->cache_path=$path; 
} 
 
//returns the filename for the cache 
private function fileName($key){ 
return $this->cache_path.md5($key); 
} 
 
//creates new cache files with the given data, $key== name of the cache, data the info/values to store 
public function put($key, $data){ 
$values = serialize($data); 
$filename = $this->fileName($key); 
$file = fopen($filename, 'w'); 
if ($file){//able to create the file 
fwrite($file, $values); 
fclose($file); 
} 
else return false; 
} 
 
//returns cache for the given key 
public function get($key){ 
$filename = $this->fileName($key); 
if (!file_exists($filename) || !is_readable($filename)){//can't read the cache 
return false; 
} 
if ( time() < (filemtime($filename) + $this->cache_expire) ) {//cache for the key not expired 
$file = fopen($filename, "r");// read data file 
if ($file){//able to open the file 
$data = fread($file, filesize($filename)); 
fclose($file); 
return unserialize($data);//return the values 
} 
else return false; 
} 
else return false;//was expired you need to create new 
} 
} 
?>