php中把数组写入到文件，再读取

Php代码

if(isset($_POST['sub'])){                 
    $cfg = array('contact'=>$_POST['contact']);  //把数据存入数组             
    file_put_contents('./data/contact.cache',serialize($cfg));  
        //把数组序列化之后，写到contact.cache里，  
    $this->redirect('other/contact');//跳转  
 }  
 else{                
    $fp = fopen('./data/contact.cache','r');//读  
    $cf = unserialize(fread($fp,filesize('./data/contact.cache')));//反序列化，并赋值  
    $this->assign('cfg',$cf);//送到前台模板  
    $this->display('other/contact');  
 }