建行B2B支付回调参数乱码现象解析

建行B2B支付采用Java开发，页面回调采用POST提交方式，编码为GBK。而我们的系统为ASP.NET，编码UTF-8。通过Request获取的参数是乱码，无奈之下，只能从InputStream解析。解析代码如下：
        log.Debug("Request Absolute Uri:" + this.Request.Url.AbsoluteUri);
            
            //GBK解析
            BinaryReader reader = new BinaryReader(this.Request.InputStream);
            Byte[] bs = reader.ReadBytes((int)this.Request.InputStream.Length);
            String parameter = HttpUtility.UrlDecode(Encoding.GetEncoding("ISO-8859-1").GetString(bs), Encoding.GetEncoding("GBK"));

            NameValueCollection parameterDic = HttpUtility.ParseQueryString(parameter);
            if (parameterDic != null && parameterDic.Count > 0)
            {
                foreach (String key in parameterDic.Keys)
                {
                    log.Debug("Query Param Key:" + key + " Value:" + parameterDic[key]);
                }
            }

服务端通知采用的GET方式，更郁闷的时，建行竟然对中文参数不做UrlEncode操作，直接用GBK编码回调过来，害得我们浪费了很长时间，还是从最原始的字节码出发，代码如下：
           log.Debug("Request Absolute Uri:" + this.Request.Url.AbsoluteUri);
            
            IServiceProvider provider = (IServiceProvider)HttpContext.Current;
            HttpWorkerRequest worker = (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
            byte[] bs = worker.GetQueryStringRawBytes();
            String queryString = Encoding.GetEncoding("GBK").GetString(bs);
            log.Debug("Query String:" + queryString);

            NameValueCollection querys = HttpUtility.ParseQueryString(queryString);
            if (querys != null && querys.Count > 0)
            {
                foreach (String key in querys.AllKeys)
                {
                   log.Debug("Query Param Key:" + key + " Value:" + querys[key]);
                }
            }