public function index(){
    $appId = 'wxd0e50fe967dccccc';
    $appSecret = 'd7f6be12ce41b60ss0f45054';//虚拟的，不要用
    $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credentialappid=".$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
  }