php实现支付宝当面付（扫码支付）功能

<"<img src='{$url}' style='width:300px;'><br>";
  echo '二维码内容：'.$result['qr_code'];
}else{
  echo $result['msg'].' : '.$result['sub_msg'];
}
class AlipayService
{
  protected $appId;
  protected $returnUrl;
  protected $notifyUrl;
  //私钥文件路径
  protected $rsaPrivateKeyFilePath;
  //私钥值
  protected $rsaPrivateKey;
  public function __construct($appid, $returnUrl, $notifyUrl,$saPrivateKey)
  {
    $this->appId = $appid;
    $this->returnUrl = $returnUrl;
    $this->notifyUrl = $notifyUrl;
    $this->charset = 'utf8';
    $this->rsaPrivateKey=$saPrivateKey;
  }
  /**
   * 发起订单
   * @param float $totalFee 收款总费用 单位元
   * @param string $outTradeNo 唯一的订单号
   * @param string $orderName 订单名称
   * @param string $notifyUrl 支付结果通知url 不要有问号
   * @param string $timestamp 订单发起时间
   * @return array
   */
  public function doPay($totalFee, $outTradeNo, $orderName, $returnUrl,$notifyUrl)
  {
    //请求参数
    $requestConfigs = array(
      'out_trade_no'=>$outTradeNo,
      'total_amount'=>$totalFee, //单位 元
      'subject'=>$orderName, //订单标题
    );
    $commonConfigs = array(
      //公共参数
      'app_id' => $this->appId,
      'method' => 'alipay.trade.precreate',       //接口名称
      'format' => 'JSON',
      'charset'=>$this->charset,
      'sign_type'=>'RSA2',
      'timestamp'=>date('Y-m-d H:i:s'),
      'version'=>'1.0',
      'notify_url' => $notifyUrl,
      'biz_content'=>json_encode($requestConfigs),
    );
    $commonConfigs["sign"] = $this->generateSign($commonConfigs, $commonConfigs['sign_type']);
    $result = $this->curlPost('https://openapi.alipay.com/gateway.do',$commonConfigs);
    return json_decode($result,true);
  }
  public function generateSign($params, $signType = "RSA") {
    return $this->sign($this->getSignContent($params), $signType);
  }
  protected function sign($data, $signType = "RSA") {
    $priKey=$this->rsaPrivateKey;
    $res = "-----BEGIN RSA PRIVATE KEY-----\n" .
      wordwrap($priKey, 64, "\n", true) .
      "\n-----END RSA PRIVATE KEY-----";
    ($res) or die('您使用的私钥格式错误，请检查RSA私钥配置');
    if ("RSA2" == $signType) {
      openssl_sign($data, $sign, $res, version_compare(PHP_VERSION,'5.4.0', '<') "")
      return true;
    return false;
  }
  public function getSignContent($params) {
    ksort($params);
    $stringToBeSigned = "";
    $i = 0;
    foreach ($params as $k => $v) {
      if (false === $this->checkEmpty($v) && "@" != substr($v, 0, 1)) {
        // 转换成目标字符集
        $v = $this->characet($v, $this->charset);
        if ($i == 0) {
          $stringToBeSigned .= "$k" . "=" . "$v";
        } else {
          $stringToBeSigned .= "&" . "$k" . "=" . "$v";
        }
        $i++;
      }
    }
    unset ($k, $v);
    return $stringToBeSigned;
  }
  /**
   * 转换字符集编码
   * @param $data
   * @param $targetCharset
   * @return string
   */
  function characet($data, $targetCharset) {
    if (!empty($data)) {
      $fileType = $this->charset;
      if (strcasecmp($fileType, $targetCharset) != 0) {
        $data = mb_convert_encoding($data, $targetCharset, $fileType);
        //$data = iconv($fileType, $targetCharset.'//IGNORE', $data);
      }
    }
    return $data;
  }
  public function curlPost($url = '', $postData = '', $options = array())
  {
    if (is_array($postData)) {
      $postData = http_build_query($postData);
    }
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $postData);
    curl_setopt($ch, CURLOPT_TIMEOUT, 30); //设置cURL允许执行的最长秒数
    if (!empty($options)) {
      curl_setopt_array($ch, $options);
    }
    //https请求 不验证证书和host
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
    $data = curl_exec($ch);
    curl_close($ch);
    return $data;
  }
}