.net 访问第三方接口，接收返回的文件流 并解压获取文件内容

//请求接口
HttpWebRequest fileReq = (HttpWebRequest)HttpWebRequest.Create(url);

//接收返回结果
HttpWebResponse fileResp = (HttpWebResponse)fileReq.GetResponse();
Stream stream = fileResp.GetResponseStream();
   System.IO.BinaryReader streamReader = new BinaryReader(stream, System.Text.Encoding.GetEncoding("UTF-8"));
//确认文件本地保存位置
string rarUrl = HttpContext.Current.Server.MapPath("~/Storage/master");
string zipName = rarUrl + "/Orders" + dateStr + ".zip";
if (System.IO.File.Exists(zipName))
{
    System.IO.File.Delete(zipName);
}
FileInfo file = new System.IO.FileInfo(zipName);
using (file.Create()){}
var l = fileResp.ContentLength.ToInt_();
FileStream fs = file.OpenWrite();
BinaryWriter fos = new BinaryWriter(fs);
var end = streamReader.ReadBytes(l);
fos.Write(end, 0, l);
fos.Flush();
fos.Close();
fs.Close();
streamReader.Close();//关闭流

读取压缩文件内的文件内容

public ActionResult ExportICBCOrdersToExcel(string zip)
    {
        var zipUrl = Server.MapPath("~/Storage/master/ICBC/" + zip);
        if (string.IsNullOrWhiteSpace(zip) || !System.IO.File.Exists(zipUrl))
        {
            throw new HimallException("错误的对账单信息");
        }

        var zipName = zip.Substring(0, zip.IndexOf("."));
        var _binPath = Server.MapPath("~/Storage/master/ICBC/" + zipName);
        if (System.IO.File.Exists(zipName))
        {
            System.IO.File.Delete(zipName);
        }
        //获取html字符串
        var html = UnZip(zipUrl, _binPath);
        //移除占位符
        var array = html.Replace("rn", "t").Split('t');
        //订单总数
        var count = array[0].Replace("u001b", "");
        //转换成models
        var models = ArrayToModel(array);

        return ExcelView("ExportICBCAccountStatement", "对账单信息", models);
    }


    /// 
 
    /// 解压功能(解压压缩文件到指定目录) 
    /// 
 
    /// 待解压的文件 
    /// 指定解压目标目录 
    /// 解压结果 
    public static string UnZip(string fileToUnZip, string zipedFolder)
    {
        var html = "";
        //解压文件
        PrepareDataFiles(zipedFolder, fileToUnZip);
        //读取文件内容
        DirectoryInfo dir = new DirectoryInfo(zipedFolder);
        foreach (FileSystemInfo fsi in dir.GetFileSystemInfos())
        {
            if (fsi is FileInfo)
            {
                FileInfo fi = (FileInfo)fsi;
                FileStream fs = fi.OpenRead();
                BinaryReader br = new BinaryReader(fs);
                var len = fi.Length.ToInt();
                var bs = br.ReadBytes(len);
                br.Close();
                fs.Close();
                html = Encoding.UTF8.GetString(bs);
            }
        }
        return html;
    }

    /// 

    /// 解压zip
    /// 
    /// 解压文件夹路径
    /// 待解压的zip路径
    private static void PrepareDataFiles(string dir, string filename)
    {
        using (ZipFile zip = ZipFile.Read(Path.Combine(filename)))
        {
            foreach (ZipEntry file in zip)
            {
                file.Extract(dir, ExtractExistingFileAction.OverwriteSilently);
            }
        }
    }

    public static List ArrayToModel(string[] array)
    {
        List list = new List();
        //第一个是订单总条数
        for (var i = 1; i < array.Length; i++)
        {
            var s = array[i].Split('u001b');
            if (string.IsNullOrWhiteSpace(array[i]) || s.Length < 45)
            {
                continue;
            }
            var model = new Model();
            model.id= s[0];
            model.name= s[1];
            list.Add(model);
        }
        return list;
    }