//实现的Wxpay钩子方法
  public function Wxpay($param){
   require './Addons/Wxpay/WxPayPubHelper/WxPayPubHelper.php';
   $jsApi = new \JsApi_pub(); 
    
   //=========步骤1：网页授权获取用户openid============
   if (!isset($_GET['code']))
   {
    //触发微信返回code码
    $url = $jsApi->createOauthUrlForCode(\WxPayConf_pub::JS_API_CALL_URL.'/order_id/'.$param['order_id']);
    Header("Location: $url");
   }else
   {
    $order_id = $param['order_id'];
    $info = M('Order')->where('id='.$order_id)->find();
    if(empty($info) || $info['is_pay'] == 1){
     dump('该订单不存在或已支付'.$order_id);
     exit();
    }
    $this->assign('info', $info);
    $a = $info['money'];
    $b = 100;
    $c = $a * $b;
     
    //获取code码，以获取openid
    $code = $_GET['code'];
    $jsApi->setCode($code);
    $openid = $jsApi->getOpenId();
   }
    
   //=========步骤2：使用统一支付接口，获取prepay_id============
   //使用统一支付接口
   $unifiedOrder = new \UnifiedOrder_pub();
    
   $unifiedOrder->setParameter("openid","$openid");//商品描述
   $unifiedOrder->setParameter("body","在线预订");//商品描述
   //自定义订单号，此处仅作举例
   $timeStamp = time();
//    $out_trade_no = \WxPayConf_pub::APPID."$timeStamp";
   $out_trade_no = $info['ordersn'];
   $unifiedOrder->setParameter("out_trade_no", "$out_trade_no");//商户订单号
   $unifiedOrder->setParameter("total_fee", "$c");//总金额
   $unifiedOrder->setParameter("notify_url",\WxPayConf_pub::NOTIFY_URL.'/order_id/'.$param['order_id']);//通知地址
   $unifiedOrder->setParameter("trade_type","JSAPI");//交易类型
    
   $prepay_id = $unifiedOrder->getPrepayId();
   //=========步骤3：使用jsapi调起支付============
   $jsApi->setPrepayId($prepay_id);
   $jsApiParameters = $jsApi->getParameters();
   $this->assign('jsApiParameters', $jsApiParameters);
 
   $this->display('pay');
  }