1、C#Socket异步、同步通信服务端、客户端源码； 2、断线重连（服务端或客户端没有启动顺序要求，先开启的等待另一端连接）；3、服务端支持同时连接多个客户端；4、阅读代码就明白通信道理，注释详细； 5、VS2015编译通过。
在网络编程中，Socket 通信是非常重要的一部分。今天咱们就来聊聊如何用 C# 实现 Socket 的异步、同步通信，并且包含断线重连功能，服务端还得支持多个客户端同时连接。整个代码基于 VS2015 编译通过。
服务端代码及分析
同步通信服务端
using System; using System.Net; using System.Net.Sockets; using System.Text; class SyncServer { private TcpListener _tcpListener; private const int BufferSize = 1024; public SyncServer() { // 初始化TcpListener，监听本地11000端口 _tcpListener = new TcpListener(IPAddress.Any, 11000); _tcpListener.Start(); Console.WriteLine("同步服务端已启动，等待客户端连接..."); } public void StartAccepting() { while (true) { // 同步接受客户端连接，这里会阻塞，直到有客户端连接进来 TcpClient client = _tcpListener.AcceptTcpClient(); Console.WriteLine("有新客户端连接：" + ((IPEndPoint)client.Client.RemoteEndPoint).Address); // 处理客户端通信 HandleClient(client); } } private void HandleClient(TcpClient client) { NetworkStream stream = client.GetStream(); byte[] buffer = new byte[BufferSize]; int bytesRead; // 从客户端读取数据，这里也是同步操作，会阻塞 while ((bytesRead = stream.Read(buffer, 0, buffer.Length))!= 0) { string message = Encoding.UTF8.GetString(buffer, 0, bytesRead); Console.WriteLine("收到客户端消息：" + message); // 给客户端回消息 string response = "服务端已收到你的消息：" + message; byte[] responseBuffer = Encoding.UTF8.GetBytes(response); stream.Write(responseBuffer, 0, responseBuffer.Length); } client.Close(); } }异步通信服务端
using System; using System.Net; using System.Net.Sockets; using System.Text; class AsyncServer { private TcpListener _tcpListener; private const int BufferSize = 1024; public AsyncServer() { _tcpListener = new TcpListener(IPAddress.Any, 11001); _tcpListener.Start(); Console.WriteLine("异步服务端已启动，等待客户端连接..."); // 开始异步接受客户端连接 BeginAccept(); } private void BeginAccept() { _tcpListener.BeginAcceptTcpClient(AcceptCallback, null); } private void AcceptCallback(IAsyncResult ar) { TcpClient client = _tcpListener.EndAcceptTcpClient(ar); Console.WriteLine("有新客户端连接：" + ((IPEndPoint)client.Client.RemoteEndPoint).Address); // 开始异步读取客户端数据 NetworkStream stream = client.GetStream(); byte[] buffer = new byte[BufferSize]; stream.BeginRead(buffer, 0, buffer.Length, ReadCallback, new StateObject { Client = client, Stream = stream, Buffer = buffer }); // 继续接受下一个客户端连接 BeginAccept(); } private void ReadCallback(IAsyncResult ar) { StateObject state = (StateObject)ar.AsyncState; TcpClient client = state.Client; NetworkStream stream = state.Stream; byte[] buffer = state.Buffer; int bytesRead = stream.EndRead(ar); if (bytesRead > 0) { string message = Encoding.UTF8.GetString(buffer, 0, bytesRead); Console.WriteLine("收到客户端消息：" + message); // 给客户端回消息 string response = "服务端已收到你的消息：" + message; byte[] responseBuffer = Encoding.UTF8.GetBytes(response); stream.BeginWrite(responseBuffer, 0, responseBuffer.Length, null, null); // 继续读取下一次数据 stream.BeginRead(buffer, 0, buffer.Length, ReadCallback, state); } else { client.Close(); } } private class StateObject { public TcpClient Client { get; set; } public NetworkStream Stream { get; set; } public byte[] Buffer { get; set; } } }服务端代码分析
- 同步服务端：使用
TcpListener监听指定端口。AcceptTcpClient方法是同步的，会阻塞线程直到有客户端连接。处理客户端通信也是同步的，Read方法会阻塞等待客户端发送数据。这种方式简单直接，但在处理多个客户端时性能不佳，因为同一时间只能处理一个客户端的请求。 - 异步服务端：同样使用
TcpListener，但通过BeginAcceptTcpClient和EndAcceptTcpClient实现异步接受客户端连接。异步读取数据时，使用BeginRead和EndRead，并且通过StateObject类来传递状态信息，这样可以在回调中继续处理客户端数据，不会阻塞主线程，能同时处理多个客户端连接。
客户端代码及分析
同步通信客户端
using System; using System.Net.Sockets; using System.Text; class SyncClient { private TcpClient _tcpClient; private const string ServerIp = "127.0.0.1"; private const int ServerPort = 11000; private const int BufferSize = 1024; public SyncClient() { Connect(); } private void Connect() { while (true) { try { _tcpClient = new TcpClient(ServerIp, ServerPort); Console.WriteLine("已连接到服务端"); break; } catch (SocketException) { Console.WriteLine("连接失败，5秒后重试..."); System.Threading.Thread.Sleep(5000); } } } public void SendMessage(string message) { NetworkStream stream = _tcpClient.GetStream(); byte[] buffer = Encoding.UTF8.GetBytes(message); stream.Write(buffer, 0, buffer.Length); byte[] responseBuffer = new byte[BufferSize]; int bytesRead = stream.Read(responseBuffer, 0, responseBuffer.Length); string response = Encoding.UTF8.GetString(responseBuffer, 0, bytesRead); Console.WriteLine("收到服务端响应：" + response); } }异步通信客户端
using System; using System.Net.Sockets; using System.Text; class AsyncClient { private TcpClient _tcpClient; private const string ServerIp = "127.0.0.1"; private const int ServerPort = 11001; private const int BufferSize = 1024; public AsyncClient() { Connect(); } private void Connect() { while (true) { try { _tcpClient = new TcpClient(); _tcpClient.BeginConnect(ServerIp, ServerPort, ConnectCallback, _tcpClient); break; } catch (SocketException) { Console.WriteLine("连接失败，5秒后重试..."); System.Threading.Thread.Sleep(5000); } } } private void ConnectCallback(IAsyncResult ar) { TcpClient client = (TcpClient)ar.AsyncState; client.EndConnect(ar); Console.WriteLine("已连接到服务端"); NetworkStream stream = client.GetStream(); byte[] buffer = new byte[BufferSize]; stream.BeginRead(buffer, 0, buffer.Length, ReadCallback, new StateObject { Client = client, Stream = stream, Buffer = buffer }); } public void SendMessage(string message) { NetworkStream stream = _tcpClient.GetStream(); byte[] buffer = Encoding.UTF8.GetBytes(message); stream.BeginWrite(buffer, 0, buffer.Length, null, null); } private void ReadCallback(IAsyncResult ar) { StateObject state = (StateObject)ar.AsyncState; TcpClient client = state.Client; NetworkStream stream = state.Stream; byte[] buffer = state.Buffer; int bytesRead = stream.EndRead(ar); if (bytesRead > 0) { string response = Encoding.UTF8.GetString(buffer, 0, bytesRead); Console.WriteLine("收到服务端响应：" + response); stream.BeginRead(buffer, 0, buffer.Length, ReadCallback, state); } else { client.Close(); } } private class StateObject { public TcpClient Client { get; set; } public NetworkStream Stream { get; set; } public byte[] Buffer { get; set; } } }客户端代码分析
- 同步客户端：
Connect方法中使用循环尝试连接服务端，如果连接失败就等待 5 秒后重试，实现了断线重连。SendMessage方法同步发送消息并接收服务端响应。 - 异步客户端：
Connect方法通过BeginConnect和EndConnect实现异步连接，连接成功后开始异步读取服务端数据。SendMessage方法异步发送消息。断线重连也是通过循环尝试连接实现的。
通过这些代码，咱们就实现了 C# Socket 的异步、同步通信，并且服务端支持多个客户端连接，客户端和服务端都具备断线重连功能，希望对大家理解 Socket 通信有所帮助。
