,net 5.0 使用Kestrel创建tcp服务器

可以使用Kestrel和System.Net.Sockets命名空间来创建TCP服务器。下面是一个简单的示例：

using System;
using System.Net;
using System.Net.Sockets;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Hosting;

namespace TcpServerExample
{
    class Program
    {
        static async Task Main(string[] args)
        {
            var host = new HostBuilder()
                .ConfigureWebHost(webHost =>
                {
                    webHost.UseKestrel(options =>
                    {
                        options.Listen(IPAddress.Any, 8080, listenOptions =>
                        {
                            listenOptions.UseConnectionHandler<CustomTcpServer>();
                        });
                    });
                })
                .Build();

            await host.RunAsync();
        }
    }

    public class CustomTcpServer : ConnectionHandler
    {
        public override async Task OnConnectedAsync(ConnectionContext connection)
        {
            var remoteEndPoint = connection.RemoteEndPoint;
            Console.WriteLine($"Client connected: {remoteEndPoint}");

            while (true)
            {
                var buffer = new byte[1024];
                var result = await connection.Transport.ReceiveAsync(new Memory<byte>(buffer));

                if (result.ConnectionClosed || result.BytesTransferred == 0)
                {
                    Console.WriteLine($"Client disconnected: {remoteEndPoint}");
                    break;
                }

                var message = System.Text.Encoding.UTF8.GetString(buffer, 0, result.BytesTransferred);
                Console.WriteLine($"Received message from {remoteEndPoint}: {message}");

                var responseMessage = $"Server received message: {message}";
                var responseBytes = System.Text.Encoding.UTF8.GetBytes(responseMessage);
                await connection.Transport.SendAsync(new ReadOnlyMemory<byte>(responseBytes));
            }
        }
    }
}

在上面的示例中，我们使用了`UseConnectionHandler`方法来指定自定义的TCP服务器处理程序。`CustomTcpServer`类继承自`ConnectionHandler`，并实现了`OnConnectedAsync`方法，这个方法在客户端连接成功时会被调用。在`OnConnectedAsync`方法中，我们使用`Transport`属性来发送和接收数据。