.Net TCP探索（一）——TCP服务端开发(同时监听多个客户端请求)

    最近在园子里看了大神写的（），忍不住写段程序来测试一番。

    在网上找了很多例子，大多只实现了tcp点对点通讯，但实际应用中，一个服务器端口往往要监听多个客户端发来的消息。

测试工具下载：
    本例采用system.threading实现多线程监听，下面只介绍核心代码，省略了消息提示和错误处理，可以从我的github获取完整代码：https://github.com/fb208/codespace/tree/master/codespace.csharp/tcp.client

数据声明：

private string _ip;//ip
private int _port;//端口
//客户端集合
public static list<tcpclientmodel> clients = new list<tcpclientmodel>
private static byte[] bytes = new byte[1024 * 100];
/// <summary>
/// 用于存储客户端
/// </summary>
public class tcpclientmodel
{
    /// <summary>
    /// ip:port
    /// </summary>
    public string remoteendpoint { get; set; }
    /// <summary>
    /// 客户端链接对象
    /// </summary>
    public tcpclient tcpclient { get; set; }
}

启动监听：

///启动监听
void init()
{
    try
    {
        ipaddress ip = ipaddress.parse(_ip);
        int port = _port;
        tcplistener listener = new tcplistener(ip, port);
        //启动监听
        listener.start();
        tb_console.appendtext($"listener...\r\n");
        //异步接收 递归循环接收多个客户端
        listener.beginaccepttcpclient(new asynccallback(getaccepttcpclient), listener);
    }
    catch (exception ex)
    {
        
    }
}

接收客户端：

private void getaccepttcpclient(iasyncresult state)
{
    //处理多个客户端接入
    tcplistener listener = (tcplistener)state.asyncstate;
    //接收到客户端请求
    tcpclient client = listener.endaccepttcpclient(state);
    //保存到客户端集合中
    clients.add(new tcpclientmodel() { tcpclient = client, remoteendpoint = client.client.remoteendpoint.tostring() });

    //开启线程用来持续接收来自客户端的数据
    thread mythread = new thread(() =>
    {
        receivemsgfromclient(client);
    });
    mythread.start();
    listener.beginaccepttcpclient(new asynccallback(getaccepttcpclient), listener);
}

接收消息并响应客户端：

private void receivemsgfromclient(object reciveclient)
{
    tcpclient client = reciveclient as tcpclient;
    if (client == null)
    {
        return;
    }
    while (true)
    {
        try
        {
            networkstream stream = client.getstream();
            int num = stream.read(bytes, 0, bytes.length); //将数据读到result中，并返回字符长度                  
            if (num != 0)
            {
                //把字节数组中流存储的数据以字符串方式赋值给str
                //这里就是接收到的客户端消息
                string str = encoding.utf8.getstring(bytes, 0, num);

                //给客户端返回一个消息
                string msg = "your message has been received by the server[" + str + "]";

                bool result = tcphelper.sendtoclient(client, msg, out msg);
                if (!result)
                {
                    //发送失败
                }
            }
            else
            {   
                //这里需要注意 当num=0时表明客户端已经断开连接，需要结束循环，不然会死循环一直卡住
                break;
            }
        }
        catch (exception ex)
        {
            //链接失败 从集合中移除出错客户端
            clients.remove(clients.firstordefault(m => m.remoteendpoint == client.client.remoteendpoint.tostring()));
            break;
        }

    }
}

从服务器向客户端发送消息的工具类：

public static class tcphelper
{
    public static bool sendtoclient(tcpclient client, string message,out string errormsg)
    {
        try
        {
            byte[] bytes = new byte[1024 * 100];
            bytes = encoding.utf8.getbytes(message);
            networkstream stream = client.getstream();
            stream.write(bytes, 0, bytes.length);
            stream.flush();
            errormsg = "";
            return true;
        }
        catch (exception ex)
        {
            errormsg = ex.message;
            return false;
        }
    }
}

测试效果：

完整代码请关注：https://github.com/fb208/codespace/tree/master/codespace.csharp/tcp.client