检测远程URL是否存在的三种方法

来源：互联网发布：晨曦软件破解版下载编辑：程序博客网时间：2024/05/18 12:39

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.XMLHTTPC

_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);//比较过时

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

return true;
}
catch (System.Net.Sockets.SocketException se)
{
System.Diagnostics.Trace.Write(se.Message);
return false;
}
}

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