public function index(){
        $appId = 'wxd0e50fe967dccccc';
        $appSecret = 'd7f6be12ce41b60ss0f45054';//虚拟的，不要用
        $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=".$appId."&secret=".$appSecret;
        $ch = curl_init();//初始化curl
        curl_setopt($ch, CURLOPT_URL,$url); //要访问的地址  
        curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);//跳过证书验证
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);  // 从证书中检查SSL加密算法是否存在
        $data = json_decode(curl_exec($ch));
        if(curl_errno($ch)){
            var_dump(curl_error($ch)); //若错误打印错误信息 
        }
        var_dump($data); //打印信息
        
        curl_close($ch);//关闭curl

    }