Crazy Learning for Day 19

1、简易客户端和服务端的聊天

• 实现客户端和服务端的消息请求和收发
• 实现多台客户端的连接，消息的异步发送
• 实现客户端的正常退出和异常退出检测

服务器端

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace TCPServer
{
    class Program
    {
        static void Main(string[] args)
        {
            StartServerASync();
            Console.ReadKey();
        }

        //同步发送消息，只能一条一条发送，需要采用异步的方式，持续不断的收发消息
        static void StartServerASync()
        {
            Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPAddress ipAddress = IPAddress.Parse("192.168.0.124");
            IPEndPoint ipEndPoint = new IPEndPoint(ipAddress, 88);
            serverSocket.Bind(ipEndPoint);//绑定ip和端口号
            serverSocket.Listen(0);//开始监听端口号

            //Socket clientSocket = serverSocket.Accept();//接收一个客户端连接
            //为了实现和多个客户端的连接，接收客户端的连接也需要使用异步的方式
            serverSocket.BeginAccept(AcceptCallBack, serverSocket);
        }

        static void AcceptCallBack(IAsyncResult ar)
        {
            Socket serverSocket = ar.AsyncState as Socket;
            Socket clientSocket = serverSocket.EndAccept(ar);

            string msg = "Hello Client! 你好...";
            byte[] data = System.Text.Encoding.UTF8.GetBytes(msg);
            clientSocket.Send(data);

            clientSocket.BeginReceive(dataBuffer, 0, 1024, SocketFlags.None, ReceiveCallBack, clientSocket);

            serverSocket.BeginAccept(AcceptCallBack, serverSocket);
        }

        static byte[] dataBuffer = new byte[1024];

        static void ReceiveCallBack(IAsyncResult ar)
        {
            Socket clientSocket = null;
            try
            {
                clientSocket = ar.AsyncState as Socket;
                int count = clientSocket.EndReceive(ar);

                if (count == 0)
                {
                    clientSocket.Close();
                    return;
                }
                string msg = Encoding.UTF8.GetString(dataBuffer, 0, count);
                Console.WriteLine("从客户端接收到数据：" + msg);
                clientSocket.BeginReceive(dataBuffer, 0, 1024, SocketFlags.None, ReceiveCallBack, clientSocket);//回调
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
                if (clientSocket != null)
                {
                    clientSocket.Close();
                }
            }

        }
    }
}

客户端

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Sockets;
using System.Net;

namespace TCPClient
{
    class Program
    {
        static void Main(string[] args)
        {
            Socket clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            clientSocket.Connect(new IPEndPoint(IPAddress.Parse("192.168.0.124"), 88));

            //客户端接收消息，收发顺序与服务器端相反
            byte[] data = new byte[1024];
            int count = clientSocket.Receive(data);//Receive执行后才继续执行下面代码
            string msg = Encoding.UTF8.GetString(data, 0, count);
            Console.Write(msg);

            while (true)
            {
                string s = Console.ReadLine();
                //Console.Write(s);
                if (s == "exit")
                {
                    clientSocket.Close();return;
                }
                clientSocket.Send(Encoding.UTF8.GetBytes(s));
            }

            Console.ReadKey();
            clientSocket.Close();

        }
    }
}

客户端和服务端之间数据的传输以数据包的形式，当短时间内每个包都很小的时候，会采用粘包的方式传输（合并再发送）；当包太大的时候，会采用分包的方式进行传输。