C#TCP

最新推荐文章于 2025-10-03 11:07:58 发布
转载最新推荐文章于 2025-10-03 11:07:58 发布 · 477 阅读
本文介绍如何使用 C# 实现 TCP 协议下的客户端和服务端通信，包括时间服务器示例、FTP 文件下载及邮件发送等示例代码。
TCPClient

TCPClient 类提供了一种使用 TCP 协议连接到某个端点的简化方法。它还通过 NetworkStream 

对象展现在连接过程中读取或写入的数据。

请参见下面从 QuickStart 文档中摘录的日期/时间客户机示例。

使用 C# 编写

using System;

using System.Net;

using System.Net.Sockets;

using System.IO;

using System.Text;

class Client

{

public static void Main(String[] args)

{

TCPClient tcpc = new TCPClient();

Byte[] read = new Byte[32];

if (args.Length != 1)

{

Console.WriteLine(“请在命令行中指定服务器名称”);

return;

}

String server = args[0];

// 验证服务器是否存在

if (DNS.GetHostByName(server) == null)

{

Console.WriteLine(“找不到服务器：” + 服务器);

return;

}

// 尝试连接到服务器

if (tcpc.Connect(server, 13) == -1)

{

Console.WriteLine(“无法连接到服务器：” + 服务器);

return;

}

// 获取流

Stream s = tcpc.GetStream();

// 读取流并将它转换为 ASCII 码形式

int bytes = s.Read(read, 0, read.Length);

String Time = Encoding.ASCII.GetString(read);

// 显示数据

Console.WriteLine(“已接收到的” + 字节 + “字节”);

Console.WriteLine(“当前日期和时间是：” + 时间);

tcpc.Close();

}

}

TCPListener

TCPListener 类便于在来自某个客户机的 TCP 连接的特定套接字上进行侦听的工作。

请参见下面包括在 QuickStart 文档中的日期/时间服务器示例。

使用 C# 编写

using System;

using System.Net;

using System.Net.Sockets;

using System.Text;

class Server

{

public static void Main()

{

DateTime now;

String strDateLine;

Encoding ASCII = Encoding.ASCII;

// 在端口 13 进行侦听

TCPListener tcpl = new TCPListener(13);

tcpl.Start();

Console.WriteLine(“正在等待客户进行连接”);

Console.WriteLine(“请按 Ctrl+c 退出...”);

while (true)

{

// 接收会阻塞，直到有人连接上

Socket s = tcpl.Accept();

// 获取当前的日期和时间并将它连接成一个字符串

now = DateTime.Now;

strDateLine = now.ToShortDateString() + " " +

now.ToLongTimeString();

// 将该字符串转换成一个字节数组并发送它

Byte[] byteDateLine =

ASCII.GetBytes(strDateLine.ToCharArray());

s.Send(byteDateLine, byteDateLine.Length, 0);

Console.WriteLine(“发送” + strDateLine);

}

}

}

这个似乎是FTP下载的：

#region "Download: File transfer FROM ftp server" 

        /// <summary> 

        /// Copy a file from FTP server to local 

        /// </summary> 

        /// <param name="sourceFilename">Target filename, if required </param> 

        /// <param name="localFilename">Full path of the local file </param> 

        /// <returns> </returns> 

        /// <remarks>Target can be blank (use same filename), or just a filename 

        /// (assumes current directory) or a full path and filename </remarks> 

        public bool Download(string sourceFilename, string localFilename

, bool PermitOverwrite) 

        { 

            //2. determine target file 

            FileInfo fi = new FileInfo(localFilename); 

            return this.Download(sourceFilename, fi, PermitOverwrite); 

        } 

        //Version taking an FtpFileInfo 

        public bool Download(FtpFileInfo file, string localFilename

, bool permitOverwrite) 

        { 

            return this.Download(file.FullName, localFilename

, permitOverwrite); 

        } 

        //Another version taking FtpFileInfo and FileInfo 

        public bool Download(FtpFileInfo file, FileInfo localFI

, bool permitOverwrite) 

        { 

            return this.Download(file.FullName, localFI

, permitOverwrite); 

        } 

        //Version taking string/FileInfo 

        public bool Download(string sourceFilename, FileInfo targetFI

, bool permitOverwrite) 

        { 

            //1. check target 

            if (targetFI.Exists && !(permitOverwrite)) 

            { 

                throw (new ApplicationException("Target file already exists")); 

            } 

            //2. check source 

            string target; 

            if (sourceFilename.Trim() == "") 

            { 

                throw (new ApplicationException("File not specified")); 

            } 

            else if (sourceFilename.Contains("/")) 

            { 

                //treat as a full path 

                target = AdjustDir(sourceFilename); 

            } 

            else 

            { 

                //treat as filename only, use current directory 

                target = CurrentDirectory + sourceFilename; 

            } 

            string URI = Hostname + target; 

            //3. perform copy 

            System.Net.FtpWebRequest ftp = GetRequest(URI); 

            //Set request to download a file in binary mode 

            ftp.Method = System.Net.WebRequestMethods.Ftp.DownloadFile; 

            ftp.UseBinary = true; 

            //open request and get response stream 

            using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse()) 

            { 

                using (Stream responseStream = response.GetResponseStream()) 

                { 

                    //loop to read & write to file 

                    using (FileStream fs = targetFI.OpenWrite()) 

                    { 

                        try 

                        { 

                            byte[] buffer = new byte[2048]; 

                            int read = 0; 

                            do 

                            { 

                                read = responseStream.Read(buffer, 0, buffer.Length); 

                                fs.Write(buffer, 0, read); 

                            } while (!(read == 0)); 

                            responseStream.Close(); 

                            fs.Flush(); 

                            fs.Close(); 

                        } 

                        catch (Exception) 

                        { 

                            //catch error and delete file only partially downloaded 

                            fs.Close(); 

                            //delete target file as it's incomplete 

                            targetFI.Delete(); 

                            throw; 

                        } 

                    } 

                    responseStream.Close(); 

                } 

                response.Close(); 

            } 

            return true; 

        } 

        #endregion

似乎是发送MAIL的

using System;

using System.Collections.Generic;

using System.Text;

using System.Net.Mail;

using System.Diagnostics;

namespace MailTest

{

     class Program

     {

         static void Main(string[] args)

         {

              Encoding encoding = Encoding.GetEncoding("GB2312");

              MailAddress from = new MailAddress("youmailname@163.com"

, "19850101", encoding);

              MailAddress to = new MailAddress("youmailname@163.com");

              MailMessage mail = new MailMessage(from, to);

              mail.Subject = "test";

              mail.Body = "hello world";

              mail.SubjectEncoding = encoding;

              mail.BodyEncoding = encoding;

              SmtpClient smtp = new SmtpClient("smtp.163.com");

              smtp.DeliveryMethod = SmtpDeliveryMethod.Network;

              smtp.UseDefaultCredentials = true;

            smtp.Credentials 

= new System.Net.NetworkCredential("rjgcwwdz@163.com", "19850101");

              smtp.Send(mail);

         }

     }

}

类似QQ通讯：

using System; 

using System.Collections.Generic; 

using System.Text; 

using System.Net; 

using System.IO; 

using System.Net.Sockets; 

using System.Threading; 

namespace MyQQSer 

{ 

    class Serv 

    { 

        private TcpListener listenr; 

        private Thread thread; 

        private bool isClose = false;    //结束程序是退出循环 

        private Socket[] sock = new Socket[50]; 

        public Serv() 

        { 

            Listener(); 

        } 

        ~Serv() 

        { 

            isClose = true; 

            for (int i = 0; i < sock.Length; i++) 

            { 

                if (sock[i] != null) 

                    sock[i].Close(); 

                listenr.Stop(); 

            } 

        } 

        /// <summary> 

        /// 开始监听端口 

        /// </summary> 

        public void Listener() 

        { 

            if (listenr == null) 

                listenr = new TcpListener(IPAddress.Parse("127.0.0.1"), 5000); 

            listenr.Start(); 

            if (thread == null) 

                thread = new Thread(new ThreadStart(ReciverMessage)); 

            thread.IsBackground = true; 

            thread.Start(); 

        } 

        /// <summary> 

        /// 接收数据 

        /// </summary> 

        private void ReciverMessage() 

        { 

            int count; //可用套结字索引 

            count = GetCount(); 

            bool loop = true; 

            if (count == -1) 

                loop = false; 

            if (loop) 

            { 

                while (true) 

                { 

                    // 判断是否退出循环 

                    if (isClose) 

                        break;                    

                    sock[count] = listenr.AcceptSocket(); 

                    Thread t = new Thread(new ThreadStart(ReciverMessage)); 

                    t.IsBackground = true; 

                    t.Start(); 

                    // 接受客户端数据 

                    while (true) 

                    { 

                        byte[] buffs = new byte[100]; 

                        if (sock[count].Connected) 

                        { 

                            try 

                            { 

                                sock[count].Receive(buffs); 

                                string message = Encoding.Default.GetString(buffs); 

                                Console.WriteLine(message); 

                                SendToAll(buffs); 

                            } 

                            catch (Exception ex) 

                            { 

                            } 

                        } 

                    } 

                } 

            } 

            Thread.CurrentThread.Abort(); 

        } 

        // 得到可用套结字索引 

        private int GetCount() 

        { 

            for (int i = 0; i < sock.Length; i++) 

                if (sock[i] == null) 

                    return i; 

            return -1; 

        } 

        // 发送消息给所有人 

        private void SendToAll(byte[] buff) 

        { 

            for (int i = 0; i < sock.Length; i++) 

            { 

                if (sock[i] != null) 

                { 

                    if (sock[i].Connected) 

                    { 

                        sock[i].Send(buff); 

                    } 

                } 

            } 

        } 

    } 

} 

using System; 

using System.Collections.Generic; 

using System.ComponentModel; 

using System.Data; 

using System.Drawing; 

using System.Text; 

using System.Windows.Forms; 

using System.Net.Sockets; 

using System.Net; 

using System.Threading; 

using System.IO; 

namespace TestClient 

{ 

    public partial class Form1 : Form 

    { 

        private TcpClient client; 

        private Thread t; 

        private Socket sock; 

        private bool close = false; 

        public Form1() 

        { 

            InitializeComponent(); 

        } 

        // 连接 

        private void btnConnect_Click(object sender, EventArgs e) 

        { 

            if(client == null) 

                client = new TcpClient(new IPEndPoint(IPAddress.Parse("127.0.0.1")

, int.Parse(txtLoalPort.Text))); 

            if (t == null) 

                t = new Thread(new ThreadStart(ReciverMessage)); 

            t.IsBackground = true; 

            t.Start(); 

            btnSend.Enabled = true; 

            btnConnect.Enabled = false; 

        } 

        // 接收消息 

        private void ReciverMessage() 

        { 

            client.Connect(IPAddress.Parse(txtSerIP.Text)

, int.Parse(txtSerPort.Text)); 

            while (true) 

            { 

                if (close) 

                    break; 

                    //NetworkStream nws = client.GetStream(); 

                    //StreamReader sr = new StreamReader(nws); 

                    //string message = sr.ReadToEnd(); 

                    //sr.Close(); 

                    if(sock == null) 

                            sock = client.Client; 

                    byte[] buff = new byte[100]; 

                    sock.Receive(buff); 

                    string message = Encoding.Default.GetString(buff); 

                    this.lstMessage.Items.Add(message);                

            } 

            Thread.CurrentThread.Abort(); 

        } 

        // 发送消息 

        private void btnSend_Click(object sender, EventArgs e) 

        { 

            string message = this.txtInput.Text; 

            byte[] buff = Encoding.Default.GetBytes(message); 

            sock.Send(buff); 

            txtInput.Text = ""; 

        } 

        private void Form1_FormClosing(object sender, FormClosingEventArgs e) 

        { 

            close = true; 

            sock.Close(); 

        } 

    } 

}