//1.创建套接字Socket
Socket _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//2.用Connect方法与服务器相连接
IPEndPoint ipPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 8080);
try
{
    _socket.Connect(ipPoint);
}
catch (SocketException e)
{
    if (e.ErrorCode == 10061)
    {
        print("服务器拒绝链接");
    }
    else
    {
        print("服务器链接失败,错误代码是：" + e.ErrorCode);
    }
}
//3.使用Send和Receive相关方法收发数据
//接收数据
byte[] receiveBytes = new byte[1024];
int receiveNum = _socket.Receive(receiveBytes);
print("收到服务端发来的消息："+Encoding.UTF8.GetString(receiveBytes, 0, receiveNum));
//发送数据、
_socket.Send(Encoding.UTF8.GetBytes("你好,这里是测试客户端一号"));
//4.用Shutdown方法释放链接
_socket.Shutdown(SocketShutdown.Both);
//5.关闭套接字
_socket.Close();

public class NetMgr : MonoBehaviour
{
    private static NetMgr instance;
    public static NetMgr Instance => instance;
    //用于存放发送消息的公共队列
    private Queue<string> sendMsgQueue = new Queue<string>();
    //用于存放收到消息的公共队列
    private Queue<string> receiveMsgQueue = new Queue<string>();
    //用于收消息的容器
    private byte[] receiveByte = new byte[1024*1024];
    //返回收到的字节数
    private int receiveNum;
    //客户端Socket
    private Socket _socket;
    //是否链接
    private bool isConnected = false;
    void Awake()
    {
        instance = this;
        DontDestroyOnLoad(this.gameObject);
    }

    
    void Update()
    {
        if (receiveMsgQueue.Count > 0)
        {
            print(receiveMsgQueue.Dequeue());
        }
    }
    
    //链接服务端
    public void Connect(string ip, int port)
    {
        //如果是链接状态就直接返回
        if(isConnected)
            return;
        
        if (_socket == null)
            _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        //链接服务端
        IPEndPoint ipPoint = new IPEndPoint(IPAddress.Parse(ip), port);
        try
        {
            _socket.Connect(ipPoint);
            isConnected = true;
            //开启发送线程
            ThreadPool.QueueUserWorkItem(SendMsg);
            //开启接收线程
            ThreadPool.QueueUserWorkItem(ReceiveMsg);
        }
        catch (SocketException e)
        {
            print("链接失败，错误代码是：" + e.ErrorCode + "/n错误信息：" + e.Message);
        }
        
    }
    //发送消息
    public void Send(string info)
    {
       sendMsgQueue.Enqueue(info);
    }

    private void SendMsg(object msg)
    {
        while (isConnected)
        {
            if (sendMsgQueue.Count > 0)
            {
                _socket.Send(Encoding.UTF8.GetBytes(sendMsgQueue.Dequeue()));
            }
        }
    }
    //不停的接收消息

    private void ReceiveMsg(object msg)
    {
        while (isConnected)
        {
            if (_socket.Available > 0)
            {
                receiveNum = _socket.Receive(receiveByte);
                //收到消息 并解析成为字符串 并放入共公共容器
                receiveMsgQueue.Enqueue(Encoding.UTF8.GetString(receiveByte,0,receiveNum));
            }
        }
    }
    public void Close()
    {
        if (_socket != null)
        {
            _socket.Shutdown(SocketShutdown.Both);
            _socket.Close();
            isConnected = false;
        }
    }

    private void OnDestroy()
    {
        Close();
    }
}