C#Socket通信

关于C#socket通信，分为同步和异步通信，本文简单介绍一下同步通信。

通信两端分别为客户端（Client）和服务器(Server):

(1)Cient:（客户端）

1：建立一个Socket对像；

2：用socket对像的Connect()方法以上面建立的EndPoint对像做为参数，向服务器发出连接请求；

3：如果连接成功，就用socket对像的Send()方法向服务器发送信息；

4：用socket对像的Receive()方法接受服务器发来的信息 ;

5：通信结束后一定记得关闭socket (未实现)；

代码有待完善，只是简单的介绍客户端的创建。（会产生粘包等问题）

仅供参考仅供参考

class Client
    {
        Socket tcpClient;

        public Client(string ip,int port) {
            //创建Socket
             tcpClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            //地址
            IPAddress iPAddress;
            if (!IPAddress.TryParse(ip,out iPAddress)) {
                Console.WriteLine("IP地址有误，创建客户端失败");
                return;
            }
            //地址：端口号
            IPEndPoint point = new IPEndPoint(iPAddress,port);

            try
            {
                tcpClient.Connect(point);//通过ip:端口号来定位一个要连接服务器
            }
            catch (Exception e) {
                Console.WriteLine(e.Message);//如果访问的服务器未打开 抛出异常信息
                return;
            }

            Console.WriteLine("连接成功");
        }

        public void Start() {
            Thread th = new Thread(SendMessage);
            th.Start();
            th.IsBackground = true;
            this.ReceiveMessage();
        }

        /// <summary>
        /// 客户端发送信息
        /// </summary>
        public void SendMessage() {
            while (true) {
                string value = Console.ReadLine();
                byte[] data = Encoding.Default.GetBytes(value);
                tcpClient.Send(data);
            }
        }

        /// <summary>
        /// 客服端接收信息
        /// </summary>
        public void ReceiveMessage() {
            try
            {
                while (true)
                {

                    byte[] arr = new byte[100 * 1024]; ;//arr用来接收数据 （相当于一个篮子）
                    int num = tcpClient.Receive(arr);
                    string data = Encoding.Default.GetString(arr, 0, num);//只把接收到的数据进行转换
                    Console.WriteLine(data);

                }
            }
            catch (Exception e) {
                Console.WriteLine("服务器已断开");
            }
        }


        
    }

(2)Server:（服务器） 

1：建立一个Socket对像；

2：用socket对像的Bind()方法绑定EndPoint；

3：用socket对像的Listen()方法开始监听；

4：接受到客户端的连接，用socket对像的Accept()方法创建新的socket对像用于和请求的客户端进行通信;

5：用新的socket对象接收（Receive）和发送（Send）消息。

代码有待完善，只是简单的介绍服务器的创建。

仅供参考仅供参考

class Server
    {
        Socket tcpServer;
        List<Socket> users = new List<Socket>();//创建客户端列表

        public Server(string ip, int port)
        {
            //1.创建socket
            tcpServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            //2.绑定IP地址和端口号

            IPAddress ipAddress;

            if (!IPAddress.TryParse(ip, out ipAddress))
            {
                Console.WriteLine("IP地址有误，创建服务器失败");
                return;
            }

            IPEndPoint point = new IPEndPoint(ipAddress, port);
            tcpServer.Bind(point);

            //限制只能100个用户接入，如果参数为0则无限制
            tcpServer.Listen(100);

        }

        public void Start()
        {
            Thread th = new Thread(UserAccept);
            th.Start();
            Thread th1 = new Thread(SendToAll);
            th1.Start();
            //Thread th2 = new Thread(ReceiveMessage);
            //th2.Start();

        }

        /// <summary>
        /// 接收用户的连接
        /// </summary>
        public void UserAccept()
        {
            Console.WriteLine("等待用户连接...");
            while (true)
            {
                Socket user = tcpServer.Accept();
                //this.ReceiveAsync(user);
                Thread thread = new Thread(ReceiveMessage);
                thread.Start(user);//每加进来一个客户端增加一个线程

                IPEndPoint str = user.RemoteEndPoint as IPEndPoint;

                Console.WriteLine(str.Address + "已连接");

                users.Add(user);
            }
        }

        /// <summary>
        /// 服务器发送信息
        /// </summary>
        public void SendToAll()
        {
            while (true)
            {
                string value = Console.ReadLine();
                byte[] data = Encoding.Default.GetBytes(value);

                for (var i = 0; i < users.Count; i++)
                {
                    try
                    {
                        users[i].Send(data);//For循环发送给每个客户端
                    }
                    catch (SocketException e)
                    {
                        IPEndPoint str = users[i].RemoteEndPoint as IPEndPoint;
                        Console.WriteLine(str.Address + "已断开连接");

                        users.RemoveAt(i);//抛出该异常说明该客户已断开连接 将其移除
                        i--;
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine(e.Message);
                    }
                }

            }
        }

        /// <summary>
        /// 服务器接收信息
        /// </summary>
        public void ReceiveMessage(object user)
        {
            Socket client = user as Socket;
            while (true)
            {
                byte[] arr = new byte[100 * 1024];
                try
                {
                    int num = client.Receive(arr);
                    string value = Encoding.Default.GetString(arr, 0, num);
                    IPEndPoint str = client.RemoteEndPoint as IPEndPoint;
                    value = str.Address + ":" + value;//把客户端的地址打印出来
                    Console.WriteLine(value);

                    SendToAll(value, client);//把客户端发过来的消息群发出去
                }
                catch (SocketException e)
                {
                    IPEndPoint str = client.RemoteEndPoint as IPEndPoint;
                    Console.WriteLine(str.Address + "已下线");
                    users.Remove(client);
                    Thread.CurrentThread.Abort();
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }
            }
        }

        /// <summary>
        /// 转发消息给其他所有客户端
        /// </summary>
        /// <param name="str">消息</param>
        /// <param name="user">发消息的客户端</param>
        public void SendToAll(string str, object user)
        {
            Socket client = user as Socket;
            byte[] data = Encoding.Default.GetBytes(str);
            for (var i = 0; i < users.Count; i++)
            {
                try
                {
                    if (client != users[i])
                    {
                        users[i].Send(data);
                    }
                }
                catch (SocketException e)
                {
                    IPEndPoint str1 = users[i].RemoteEndPoint as IPEndPoint;
                    Console.WriteLine(str1.Address + "已下线");

                    users.RemoveAt(i);
                    i--;
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }
            }

        }
}

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