返回通知校验

使用POST方式请求到下单时填写的server_notify_url网址，使用POST接收结果

$post_data = array(
    'serial'=>$_POST['serial'],
    'serial_number'=>$_POST['serial_number'],
    'amount'=>$_POST['amount'],
    'openid'=>$_POST['openid'],
    'remark1'=>$_POST['remark1'],
    'remark2'=>$_POST['remark2'],
    'status'=>$_POST['status'],//status值：success支付成功 fail支付失败
);

$sign = $_POST['sign'];

//键值排序  
ksort($post_data);
$str = '';
foreach($post_data as $k=>$v){
    $str .= $k.'='.$v.'&';
}
$str .= 'key=平台分配';

if(md5($str) == $sign){
    echo 'success';
}