多线程HtttpRequest 一定要记得关闭reponse

public static bool WebFileExistsWithClose(string url, int timeoutSeconds)
{
HttpWebResponse response = null;
bool flag;
try
{
HttpWebRequest request = (HttpWebRequest) WebRequest.Create(url);
request.Timeout = timeoutSeconds * 1000；

request.AllowAutoRedirect = true;
request.MaximumAutomaticRedirections = 200;
response = (HttpWebResponse) request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
return true;
}
flag = false;
}
catch (WebException)
{
flag = false;
}
catch (Exception exception)
{
throw exception;
}
finally
{
if (response != null)
{
response.Close();
}
}
return flag;
}