Question

我有一个程序需要下载约200行~250行的XML页面。它通过从主页面中获取ID列表来完成此操作，然后它遍历每个ID，将其插入URL并使用StreamWriter将XML页面写入文件。方法如下所示：

    private static void XMLUpdate(string path)
    {
        try
        {
            //create client for downloading XMLs
            var client = new WebClient();

            foreach (var node in GetId())
            {
                //stores xml text into a string
                var s = client.DownloadString("https://example" + node + "/xml");

                // assign to the output
                var file = new StreamWriter(path + "\\" + node + ".xml");
                file.WriteLine(s);
                file.Close();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

    private static string[] GetId()
    {
        var idList = new List<string>();
        var request = WebRequest.Create("https://example/xml");

        var i = 0;

        using (var response = request.GetResponse())
        using (var xmlReader = XmlReader.Create(response.GetResponseStream()))
        {
            while (xmlReader.Read())
            {
                xmlReader.ReadToFollowing("n" + i);
                //go through each of the n nodes in the xmldocument and get the name and id
                if (xmlReader.NodeType != XmlNodeType.Element || xmlReader.Name != "n" + i) continue;
                xmlReader.ReadToFollowing("id");

                if (xmlReader.NodeType == XmlNodeType.Element && xmlReader.Name == "id")
                {
                    var id = xmlReader.ReadElementContentAsString();
                    idList.Add(id);
                }

                i += 1;
            }
        }

        var IDs = idList.ToArray();

        return IDs;
    }

目前该程序需要很长时间才能下载我需要的所有内容。我有什么办法可以加快这个过程吗？

Answer 1

是的，您可以使用Parallel.ForEach：

并行运行

Parallel.ForEach
( GetId()
, new ParallelOptions() { MaxDegreeOfParallelism = 32 } // run 32 in parallel
, node =>
  {
    //stores xml text into a string
    var client = new WebClient();
    var s = client.DownloadString("https://example" + node + "/xml");

    // assign to the output
    var file = new StreamWriter(path + "\\" + node + ".xml");
    file.WriteLine(s);
    file.Close();
  }
);

您可以根据需要调整MaxDegreeOfParallelism，服务可以处理。

我可以加快下载XML页面的代码吗？

1 个答案: