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1. Overview 1. WebRequest:

Make a request for the uniform Resource Identifier (URI). This is an abstract class.

Derived classes of WebRequest: PackWebRequest, FileWebRequest, FtpWebRequest, HttpWebRequest

Important: we do not recommend that you use new development of WebRequest or its derived classes. Please use the System.Net.Http.HttpClient class above Net4.5.

2 、 WebResponse

Provides a response from the uniform Resource Identifier (URI). This is an abstract class.

WebResponse derived classes: PackWebResponse, FileWebResponse, FtpWebResponse, HttpWebResponse

The client application does not create the WebResponse object directly; it is created by calling the GetResponse method of the WebRequest instance.

Download 1. Synchronization mode WebRequest request = WebRequest.Create ("http://www.baidu.com");// can convert request to HttpWebRequest to set and get a specific property request.Credentials = CredentialCache.DefaultCredentials;//. You can also set proxy request.Proxy..request.Timeout = 1000 request.GetResponse response response = request.GetResponse (); / / get the response. There are asynchronous methods: Begin/EndGetResponseStream stream = response.GetResponseStream (); / / get the response flow, read the response flow, download using (StreamReader reader = new StreamReader (stream, Encoding.UTF8)) / / or stream.Read (buffer) {Console.WriteLine (reader.ReadToEnd ());} 2, asynchronous mode WebRequest request = WebRequest.Create ("http://www.baidu.com"); / / you can cast request to HttpWebRequest to set and get a specific property request.BeginGetResponse (ar = > {WebRequest request_1 = (WebRequest) ar.AsyncState; WebResponse response = request_1.EndGetResponse (ar); Stream stream = response.GetResponseStream (); / / get response flow using (StreamReader reader = new StreamReader (stream, Encoding.UTF8)) / / or stream.Read (buffer) {Console.WriteLine (reader.ReadToEnd ());}}, request) 3. Above Net4.5, Task is asynchronous. Void Main () {GetResponseAsync ()} public async void GetResponseAsync () {WebRequest request = WebRequest.Create ("http://www.baidu.com");// can cast request to HttpWebRequest to set and get specific properties WebResponse response = await request.GetResponseAsync () as WebResponse; Stream stream = response.GetResponseStream () / / get response stream using (StreamReader reader = new StreamReader (stream, Encoding.UTF8)) / / you can also stream.Read (buffer) {Console.WriteLine (reader.ReadToEnd ());}} III. Upload: 1. HTTP upload: 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 (); / / get request stream, write stream, upload or asynchronously: Begin/EndGetRequestStreamstream.Write (buffer, 0, buffer.Length); HttpWebResponse response = (HttpWebResponse) request.GetResponse (); using (StreamReader reader = new StreamReader (response.GetResponseStream (), Encoding.UTF8) {Console.WriteLine (reader.ReadToEnd () 2. FTP upload file code implementation: (for FTP, Microsoft recommends using third-party tools) 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 ()

FtpWebRequest and FtpWebResponse complete the FTP operation

FTP tools FileZilla, WinSCP, FTP class library FluentFTP

4. DNS static class

The Dns class is a static class that retrieves information about a specific host from the Internet Domain name system (DNS).

IPHostEntry class in the instance returned by the host information in the DNS query. If the specified host is in the DNS database, there are multiple entries IPHostEntry that contain multiple IP addresses and aliases.

1. DNS class method

GetHostName () gets the hostname of the local computer.

GetHostAddresses (String) returns the Internet Protocol (IP) address of the specified host. Returns the IPAddress [] array

GetHostEntry (String) resolves the hostname or IP address to the IPHostEntry instance.

GetHostByAddress (String) creates an IPHostEntry instance based on the IP address.

GetHostEntry (IPAddress) resolves the IP address to the IPHostEntry instance.

GetHostByAddress (IPAddress) creates an IPHostEntry instance based on the specified IPAddress.

Resolve (String) resolves the DNS hostname or IP address to an IPHostEntry instance.

2. IPHostEntry attribute

AddressList gets or sets the list of IP addresses associated with the host. Returns the IPAddress [] array

Aliases gets or sets the list of aliases associated with the host.

HostName gets or sets the DNS name of the host.

Fifth, ping class

The Ping class is located under System.Net.NetworkInformation.

Bool online = false; / / whether online try {Ping ping = new Ping (); PingReply pingReply = ping.Send ("192.168.132.191"); / / hostname or IP address if (pingReply.Status = = IPStatus.Success) {online = true; Console.WriteLine ("currently online, pingtong!") ;} else {Console.WriteLine ("not online, ping is not available!") ;}} catch {Console.WriteLine ("not online, ping is not available!") ;} these are all the contents of this article entitled "WebRequest and WebResponse Abstract Class, DNS static Class and ping Class instance Analysis in C#". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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