php xpath 获取网页a链接 href值

    public function handle()    
    {
       $url = 'http://www.biochemsafebuy.com/m/category_detailed/0';
       $this->spiderList($url);
    }
    private function spiderList($url){
       Log::info('list_url', [$url]);
       $html = file_get_contents($url);
       $dom = new \DOMDocument();
       @$dom->loadHTML($html);
       $dom->normalize();
       $xpath = new \DOMXPath($dom);
       //$lists = $xpath->query('.//div[contains(@class, "wrap-img")]/a/text()');
       $lists = $xpath->query('.//div[contains(@class, "wrap-img")]/a/@href');
       foreach ($lists as $node) {
            $detail_url = $node->nodeValue;
            Log::info('detail_url', [$detail_url]);
       }
    }