public function getAccessToken()
{
$res = S('yZAccessToken');
if ($res) {//這邊都是false
echo 1;//一直都是不會列印
return $res;
    } else {
$yZGetTokenClient = new \YZGetTokenClient( $this->client_id , $this->client_secret );
$accessToken =  $yZGetTokenClient->get_token($this->type, $this->keys);
        S(
 
'yzAccessToken', $accessToken['access_token'], $accessToken['expires_in']);
return $accessToken['access_token'];
    }
}

public function getAccessToken()
{
$res = S('yzaccesstoken');
if ($res) {

echo 1;//這邊快取就有效果
return $res;
    } else {
$yZGetTokenClient = new \YZGetTokenClient( $this->client_id 
 
, $this->client_secret );
$accessToken =  $yZGetTokenClient->get_token($this->type, $this->keys);
        S('yzaccesstoken', $accessToken['access_token'], $accessToken['expires_in']);
return $accessToken['access_token'];
    }
}

具體未去看底層實現，有時間再研究