private function __CreateOauthUrlForOpenid($code)
{
$urlObj["appid"] = WxPayConfig::APPID;
$urlObj["secret"] = WxPayConfig::APPSECRET;
$urlObj["code"] = $code;
$urlObj["grant_type"] = "authorization_code";
$bizString = $this->ToUrlParams($urlObj);
return "https://api.weixin.qq.com/sns/oauth2/access_token?" . $bizString;
}