非常清晰的demo

服務端

using System;
using System.Collections;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UnityEngine;

public class SocketServer : MonoBehaviour {

	// Use this for initialization
	public void StartServer () {
        bt_connnect_Click();
    }
	
	// Update is called once per frame
	void Update () {
		
	}

    private void bt_connnect_Click()
    {
        try
        {
            int _port = 6000;
            string _ip = "127.0.0.1";

            //點擊開始監聽時 在服務端創建一個負責監聽IP和端口號的Socket
            Socket socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPAddress ip = IPAddress.Parse(_ip);
            //創建對象端口
            IPEndPoint point = new IPEndPoint(ip, _port);

            socketWatch.Bind(point);//綁定端口號
            Debug.Log("監聽成功!");
            socketWatch.Listen(10);//設置監聽，最大同時連接10臺

            //創建監聽線程
            Thread thread = new Thread(Listen);
            thread.IsBackground = true;
            thread.Start(socketWatch);
        }
        catch { }

    }

    /// <summary>
    /// 等待客戶端的連接 並且創建與之通信的Socket
    /// </summary>
    Socket socketSend;
    void Listen(object o)
    {
        try
        {
            Socket socketWatch = o as Socket;
            while (true)
            {
                socketSend = socketWatch.Accept();//等待接收客戶端連接
                Debug.Log(socketSend.RemoteEndPoint.ToString() + ":" + "連接成功!");
                //開啟一個新線程，執行接收消息方法
                Thread r_thread = new Thread(Received);
                r_thread.IsBackground = true;
                r_thread.Start(socketSend);
            }
        }
        catch { }
    }

    /// <summary>
    /// 服務器端不停的接收客戶端發來的消息
    /// </summary>
    /// <param name="o"></param>
    void Received(object o)
    {
        try
        {
            Socket socketSend = o as Socket;
            while (true)
            {
                //客戶端連接服務器成功後，服務器接收客戶端發送的消息
                byte[] buffer = new byte[1024 * 1024 * 3];
                //實際接收到的有效字節數
                int len = socketSend.Receive(buffer);
                if (len == 0)
                {
                    break;
                }
                string str = Encoding.UTF8.GetString(buffer, 0, len);
                Debug.Log("服務器打印：" + socketSend.RemoteEndPoint + ":" + str);
                Send("我收到了");
            }
        }
        catch { }
    }

    /// <summary>
    /// 服務器向客戶端發送消息
    /// </summary>
    /// <param name="str"></param>
    void Send(string str)
    {
        byte[] buffer = Encoding.UTF8.GetBytes(str);
        socketSend.Send(buffer);
    }
}

客戶端

using System;
using System.Collections;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UnityEngine;
using UnityEngine.UI;

public class SocketClient : MonoBehaviour {

    public InputField input;

    
 
// Use this for initialization
    public void StartClient () {
        bt_connect_Click();
    }
    
    // Update is called once per frame
    void Update () {
        
    }

    public void SendMsg()
    {
        bt_send_Click(input.text);
    }

    Socket socketSend;
    private void
 
 bt_connect_Click()
    {
        try
        {
            int _port = 6000;
            string _ip = "127.0.0.1";

            //創建客戶端Socket，獲得遠程ip和端口號
            socketSend = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPAddress ip = IPAddress.Parse(_ip);
            IPEndPoint point = new IPEndPoint(ip, _port);

            socketSend.Connect(point);
            Debug.Log("連接成功!");
            //開啟新的線程，不停的接收服務器發來的消息
            Thread c_thread = new Thread(Received);
            c_thread.IsBackground = true;
            c_thread.Start();
        }
        catch (Exception)
        {
            Debug.Log("IP或者端口號錯誤...");
        }

    }

    /// <summary>
    /// 接收服務端返回的消息
    /// </summary>
    void Received()
    {
        while (true)
        {
            try
            {
                byte[] buffer = new byte[1024 * 1024 * 3];
                //實際接收到的有效字節數
                int len = socketSend.Receive(buffer);
                if (len == 0)
                {
                    break;
                }
                string str = Encoding.UTF8.GetString(buffer, 0, len);
                Debug.Log("客戶端打印：" + socketSend.RemoteEndPoint + ":" + str);
            }
            catch { }
        }
    }

    /// <summary>
    /// 向服務器發送消息
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void bt_send_Click(string str)
    {
        try
        {
            string msg = str;
            byte[] buffer = new byte[1024 * 1024 * 3];
            buffer = Encoding.UTF8.GetBytes(msg);
            socketSend.Send(buffer);
        }
        catch { }
    }
}

unity Socket TCP連接案例（一）