检测远程URL是否存在的三种方法<转>

检测远程URL是否存在的三种方法

来源：孟子E章 关键词：URL  存在  

 

private void Page_Load(object sender, System.EventArgs e)

{

  string url1 = "http://dotnet.aspx.cc/";

  string url2 = "http://dotnet.aspx.cc/Images/logo.gif";

  Response.Write("<li>方法1：");

  Response.Write(url1 + " 存在：" + UrlExistsUsingHttpWebRequest(url1).ToString());

  Response.Write("<li>方法2：");

  Response.Write(url1 + " 存在：" + UrlExistsUsingSockets(url1).ToString());

  Response.Write("<li>方法3：");

  Response.Write(url1 + " 存在：" + UrlExistsUsingXmlHttp(url1).ToString());

  Response.Write("<li>方法1：");

  Response.Write(url2 + " 存在：" + UrlExistsUsingHttpWebRequest(url2).ToString());

  Response.Write("<li>方法3：");

  Response.Write(url2 + " 存在：" + UrlExistsUsingXmlHttp(url2).ToString());

}



private bool UrlExistsUsingHttpWebRequest(string url){

  try

  {

    System.Net.HttpWebRequest myRequest = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(url);

    myRequest.Method = "HEAD";

    myRequest.Timeout = 100;

    System.Net.HttpWebResponse res = (System.Net.HttpWebResponse)myRequest.GetResponse();

    return (res.StatusCode == System.Net.HttpStatusCode.OK);

  }

  catch (System.Net.WebException we)

  {

    System.Diagnostics.Trace.Write(we.Message);

    return false;

  }

}



private bool UrlExistsUsingXmlHttp(string url)

{

  //注意：此方法需要引用Msxml2.dll

  MSXML2.XMLHTTP _xmlhttp = new MSXML2.XMLHTTPClass();

  _xmlhttp.open("HEAD", url, false, null, null);

  _xmlhttp.send("");

  return (_xmlhttp.status == 200);

}

private bool UrlExistsUsingSockets(string url)

{

  if (url.StartsWith("http://")) url = url.Remove(0, "http://".Length);

  try

  {

    System.Net.IPHostEntry ipHost = System.Net.Dns.Resolve(url);

    return true;

  }

  catch (System.Net.Sockets.SocketException se)

  {

    System.Diagnostics.Trace.Write(se.Message);

    return false;

  }

}