C#中的WebRequest与WebResponse抽象类、DNS静态类、Ping类介绍

WebRequest request = WebRequest.Create("http://www.baidu.com");//可以将request强制转换为HttpWebRequest，以设置和获取特定的属性
request.Credentials = CredentialCache.DefaultCredentials;//也可以设置代理request.Proxy..
request.Timeout = 1000;

WebResponse response = request.GetResponse
();//获取响应.有异步方法：Begin/EndGetResponse
Stream stream = response.GetResponseStream();//
获取响应流，读取响应流，进行下载
using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))//也可以stream.Read(buffer)
{
    Console.WriteLine(reader.ReadToEnd());
}

WebRequest request = WebRequest.Create("http://www.baidu.com");//可以将request强制转换为HttpWebRequest，以设置和获取特定的属性

request.BeginGetResponse(ar =>{
    WebRequest request_1 = (WebRequest)ar.AsyncState;
    WebResponse response = request_1.EndGetResponse(ar);
    Stream stream = response.GetResponseStream();//获取响应流
    using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))//也可以stream.Read(buffer)
    {
        Console.WriteLine(reader.ReadToEnd());
    }
}, request);

void Main()
{
    GetResponseAsync();
}

public async void GetResponseAsync()
{
    WebRequest request = WebRequest.Create("http://www.baidu.com");//可以将request强制转换为HttpWebRequest，以设置和获取特定的属性
    WebResponse response = await request.GetResponseAsync() as WebResponse;

    Stream stream = response.GetResponseStream();//获取响应流
    using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))//也可以stream.Read(buffer)
    {
        Console.WriteLine(reader.ReadToEnd());
    }
}

Encoding encoding = Encoding.Default;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.baidu.com");
request.Method = "post";
request.Accept = "text/html, application/xhtml+xml, */*";
request.ContentType = "application/x-www-form-urlencoded";
byte[] buffer = encoding.GetBytes("aaa");
request.ContentLength = buffer.Length;
Stream stream = request.GetRequestStream();//获取请求流，进行写入流
,进行上传或者异步：Begin/EndGetRequestStream

stream.Write(buffer, 0, buffer.Length);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
{
    Console.WriteLine(reader.ReadToEnd());
}

string ftphost = "127.0.0.1";
//here correct hostname or IP of the ftp server to be given  

string ftpfullpath = "ftp://" + ftphost + "/testfolder/testfile.xml";
FtpWebRequest ftp = (FtpWebRequest)FtpWebRequest.Create(ftpfullpath);
ftp.Credentials = new NetworkCredential("userid", "password");
//userid and password for the ftp server to given  

ftp.KeepAlive = true;
ftp.UseBinary = true;
ftp.Method = WebRequestMethods.Ftp.UploadFil;
FileStream fs = File.OpenRead(@"c:\testfile.xml");
byte[] buffer = new byte[fs.Length];
fs.Read(buffer, 0, buffer.Length);
fs.Close();
Stream ftpstream = ftp.GetRequestStream();
ftpstream.Write(buffer, 0, buffer.Length);
ftpstream.Close();

bool online = false; //是否在线
try
{

    Ping ping = new Ping();
    PingReply pingReply = ping.Send("192.168.132.191");//主机名或者IP地址
    if (pingReply.Status == IPStatus.Success)
    {
        online = true;
        Console.WriteLine("当前在线，已ping通！");
    }
    else
    {
        Console.WriteLine("不在线，ping不通！");
    }
}
catch
{
    Console.WriteLine("不在线，ping不通！");
}