如果我們要處理客戶端的每一條消息，針對與上面的粘包的問題，我們無法處理消息的涧尿，我們不知道消息到底有多長（雖說我們的案例是一樣的，但實際開發(fā)中可能是不一樣的）檬贰，那么我們就要涉及到分包的問題了姑廉。

在上一篇的文章中我們可以看到一篇文章被接受了多次才接受完，加入客戶端一下發(fā)了多篇文章翁涤？那么我們怎么才能把每一篇文章分出來呢桥言？這就涉及到了分包。
我們在客戶端每次發(fā)消息的時候我們都要將發(fā)送信息的長度加到消息的前面迷雪。由于TCP消息都是按順序到達的限书，那么我們在讀消息的時候，先讀出消息長度（len）章咧，然后從消息長度后開始讀取len個字節(jié)，那么這len個字節(jié)就是我們要的消息能真。
對前面的代碼進行修改如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;

namespace ASYNServer
{
    class Server
    {
        private TcpListener tcpListener;
        byte[] buffer = new byte[512];
        /// <summary>
        /// 接受消息
        /// </summary>
        List<byte> receiveDataList = new List<byte>();
        public Server()
        {
            tcpListener = new TcpListener(new IPEndPoint(IPAddress.Parse("127.0.0.1"),10001));
            //開啟偵聽赁严，最多只能連接20個客戶端數(shù)目
            tcpListener.Start(20);
            tcpListener.BeginAcceptSocket(ClientConnect, tcpListener);
        }
        /// <summary>
        /// 客戶端連接
        /// </summary>
        /// <param name="ar"></param>
        private void ClientConnect(IAsyncResult ar)
        {
            try
            {
                TcpListener listener = (TcpListener)ar.AsyncState;
                Socket client = listener.EndAcceptSocket(ar);
                Console.WriteLine(client.RemoteEndPoint.ToString() + "連接成功");
                //偵聽結(jié)束后開始接收數(shù)據(jù)
                ReceiveData(client);
                //重新偵聽是否有新的客戶端連接
                //如果這里不寫  那么只能偵聽一次
                tcpListener.BeginAcceptSocket(ClientConnect, tcpListener);
            }
            catch (Exception e)
            {

                Console.WriteLine("ClientConnect"+e.Message);
            }
        }
        /// <summary>
        /// 接受數(shù)據(jù)的回調(diào)
        /// </summary>
        /// <param name="client"></param>
        private  void ReceiveData(Socket client)
        {
            SocketError socketError;
            client.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, out socketError, ReceiveCallback, client);
        }
        /// <summary>
        /// 一次接收的數(shù)據(jù)的長度
        /// </summary>
        int receLen = 0;
        private void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                SocketError socketError;
                Socket client = (Socket)ar.AsyncState;
                receLen = client.EndReceive(ar, out socketError);
                if (receLen>0)
                {
                    lock (receiveDataList)
                    {
                        //處理接收到的數(shù)據(jù)

                        OnReceiveData(client);
                    }
                    
                }else//當receLen<=0的時候表示客戶端斷開和服務(wù)器的連接
                {
                    Console.WriteLine(client.LocalEndPoint.ToString()+"關(guān)閉了");
                }
                //重新接受數(shù)據(jù)
                ReceiveData(client);
            }
            catch (Exception e)
            {
                Console.WriteLine("ReceiveCallback:" + e.Message + "   "+e.StackTrace);
            }
        }
        /// <summary>
        /// 接受數(shù)據(jù)
        /// </summary>
        /// <param name="socket"></param>
        private void OnReceiveData(Socket socket)
        {
            
            byte[] tempArr = new byte[receLen];
            Array.Copy(buffer, tempArr, receLen);
            receiveDataList.AddRange(tempArr);

            if (receiveDataList.Count>=4)
            {
                byte[] dataArray = receiveDataList.GetRange(0, 4).ToArray();
                int len = BitConverter.ToInt32(dataArray, 0);
                
                if (receiveDataList.Count>=len+4)
                {
                    receiveDataList.RemoveRange(0, 4);
                    dataArray = receiveDataList.GetRange(0, len).ToArray();
                    string message = Encoding.UTF8.GetString(dataArray, 0, len);
                    receiveDataList.RemoveRange(0, len);
                    Console.WriteLine("來自客戶端的數(shù)據(jù)是:" + message);
                    Console.WriteLine();
                }
            }
        }
        /// <summary>
        /// 發(fā)送數(shù)據(jù)
        /// </summary>
        /// <param name="socket"></param>
        /// <param name="data"></param>
        public void SendData(Socket socket, byte[] data)
        {
            SocketError socketError;
            socket.BeginSend(data, 0, data.Length, SocketFlags.None, out socketError, SendCallBack, socket);//異步發(fā)送數(shù)據(jù)
        }
        /// <summary>
        /// 發(fā)送數(shù)據(jù)的回調(diào)
        /// </summary>
        /// <param name="ar"></param>
        private void SendCallBack(IAsyncResult ar)
        {
            SocketError socketError;
            Socket client = (Socket)ar.AsyncState;
            client.EndSend(ar, out socketError);
        }
    }
}

客戶端代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.IO;

namespace ASYNClient
{
    class Client
    {
        private TcpClient tcpclient = null;
        byte[] result;
        public Client()
        {
            tcpclient = new TcpClient();
            //連接服務(wù)器
            tcpclient.BeginConnect(IPAddress.Parse("127.0.0.1"), 10001, ConnectCallback, tcpclient);
        }
        /// <summary>
        /// 連接回調(diào)
        /// </summary>
        /// <param name="ar"></param>
        private void ConnectCallback(IAsyncResult ar)
        {
            TcpClient client = (TcpClient)ar.AsyncState;
            try
            {
                if (client.Connected)
                {
                    //連接成功
                    client.EndConnect(ar);
                    //開始接受數(shù)據(jù)
                    ReceiveData(client);

                }
            }
            catch (Exception e)
            {
                Console.WriteLine("ConnectCallback："+e.Message);
            }
        }
        /// <summary>
        /// 接收數(shù)據(jù)
        /// </summary>
        /// <param name="client"></param>
        private void ReceiveData(TcpClient client)
        {
            NetworkStream stream = client.GetStream();

            result = new byte[client.Available];
          
            try
            {
                stream.BeginRead(result, 0, result.Length, ReadCallBack, stream);
            }
            catch (Exception e)
            {
                Console.WriteLine("ReceiveData:"+e.Message );
            }
        }
        /// <summary>
        /// 接受消息回調(diào)
        /// </summary>
        /// <param name="ar"></param>
        private void ReadCallBack(IAsyncResult ar)
        {
            NetworkStream stream;
            try
            {
                stream = (NetworkStream)ar.AsyncState;
                stream.EndRead(ar);
            }
            catch (IOException e)
            {
                Console.WriteLine("遠程服務(wù)器關(guān)閉");
                
            }
           
        }
        /// <summary>
        /// 發(fā)送消息
        /// </summary>
        /// <param name="data"></param>
        public void SendData(byte[] data)
        {
            if (tcpclient.Connected)
            {
                NetworkStream stream = tcpclient.GetStream();
                stream.BeginWrite(data,0,data.Length, SendCallback, stream);

            }
        }
        /// <summary>
        /// 發(fā)送消息回調(diào)
        /// </summary>
        /// <param name="ar"></param>
        private void SendCallback(IAsyncResult ar)
        {
            NetworkStream stream = (NetworkStream)ar.AsyncState;
            stream.EndWrite(ar);
        }
    }
}

客戶端測試代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ASYNClient
{
    class Program
    {
        static void Main(string[] args)
        {
            Client client = new Client();
            //等待客戶端連接服務(wù)器后我們按下回車鍵模擬客戶端一次性發(fā)送多條數(shù)據(jù)
            Console.ReadLine();
            for (int i = 0; i < 3; i++)
            {
                //string message = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
                string message = "燕子去了扰柠，有再來的時候；楊柳枯了疼约，有再青的時候卤档；桃花謝了，有再開的時 候程剥。但是劝枣，聰明的，你告訴我织鲸，我們的日子為什么一去不復返呢舔腾？——是有人偷了他 們罷：那是誰？又藏在何處呢搂擦？是他們自己逃走了罷——如今又到了哪里呢稳诚？我不知道他們給了我多少日子，但我的手確乎（1）是漸漸空虛（2）了瀑踢。在默默里算著扳还，八千多日子已經(jīng)從我手中溜去，像針尖上一滴水滴在大海里橱夭，我的日子滴在時間的流里氨距，沒有聲音，也沒有影子棘劣。我不禁頭涔涔（3）而淚潸潸（4）了衔蹲。去的盡管去了，來的盡管來著呈础；去來的中間舆驶，又怎樣地匆匆呢？早上我起來的時候而钞，小屋里射進兩三方斜斜的太陽沙廉。太陽他有腳啊，輕輕悄悄地挪移了臼节；我也茫茫然跟著旋轉(zhuǎn)撬陵。于是——洗手的時候，日子從水盆里過去网缝；吃飯的時候巨税，日子從飯碗里過去；默默時粉臊，便從凝然的雙眼前過去草添。我覺察他去的匆匆了，伸出手遮挽時扼仲，他又從遮挽著的手邊過去远寸，天黑時抄淑，我躺在床上，他便伶伶俐俐（5）地從我身上跨過驰后，從我腳邊飛去了肆资。等我睜開眼和太陽再見，這算又溜走了一日灶芝。我掩著面嘆息郑原。但是新來的日子的影兒又開始在嘆息里閃過了。在逃去如飛的日子里夜涕，在千門萬戶的世界里的我能做些什么呢犯犁？只有徘徊（6）罷了（7），只有匆匆罷了钠乏；在八千多日的匆匆里栖秕，除徘徊外，又剩些什么呢晓避？過去的日子如輕煙簇捍，被微風吹散了，如薄霧俏拱，被初陽蒸融了暑塑；我留著些什么痕跡呢？我何曾留著像游絲（8）樣的痕跡呢锅必？我赤裸裸來到這世界事格，轉(zhuǎn)眼間也將赤裸裸的回去罷？但不能平的搞隐，為什么偏要白白走這一遭熬杂蕖？你聰明的劣纲，告訴我逢捺，我們的日子為什么一去不復返呢？"; 
                byte[] messageData = Encoding.UTF8.GetBytes(message);
                Console.WriteLine("messageData:"+ messageData.Length);
                byte[] lenData = BitConverter.GetBytes(messageData.Length);
                byte[] data = new byte[lenData.Length+messageData.Length];
                Array.Copy(lenData, data, lenData.Length);
                Array.Copy(messageData,0,data,lenData.Length,messageData.Length);
                client.SendData(data);
            }
            Console.ReadLine();
        }
    }
}

測試結(jié)果