代码改变世界

Socket的select模型

2011-07-04 22:40  Clingingboy  阅读(15084)  评论(2编辑  收藏  举报

 

注意点:发送的时候字节数不要发送…我就悲剧的测试数据发错了,以为哪出问题了

思路:

  1. 初始化一个socket
  2. 建立一个socket列表用于管理socket
  3. 将初步连接的socket放入列表中
  4. 用select判断列表中未处理的socket

Win API版本

1.

USHORT nPort = 4567;    // 此服务器监听的端口号

// 创建监听套节字
SOCKET sListen = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);    
sockaddr_in sin;
sin.sin_family = AF_INET;
sin.sin_port = htons(nPort);
sin.sin_addr.S_un.S_addr = INADDR_ANY;
// 绑定套节字到本地机器
if(::bind(sListen, (sockaddr*)&sin, sizeof(sin)) == SOCKET_ERROR)
{
    printf(" Failed bind() \n");
    return -1;
}
// 进入监听模式
::listen(sListen, 5);

2.

    // select模型处理过程
// 1)初始化一个套节字集合fdSocket,添加监听套节字句柄到这个集合
fd_set fdSocket;        // 所有可用套节字集合
FD_ZERO(&fdSocket);
FD_SET(sListen, &fdSocket);

3.

while(TRUE)
{
    // 2)将fdSocket集合的一个拷贝fdRead传递给select函数,
    // 当有事件发生时,select函数移除fdRead集合中没有未决I/O操作的套节字句柄,然后返回。
    fd_set fdRead = fdSocket;
    int nRet = ::select(0, &fdRead, NULL, NULL, NULL);
    if(nRet > 0)
    {
        // 3)通过将原来fdSocket集合与select处理过的fdRead集合比较,
        // 确定都有哪些套节字有未决I/O,并进一步处理这些I/O。
        for(int i=0; i<(int)fdSocket.fd_count; i++)
        {
            if(FD_ISSET(fdSocket.fd_array[i], &fdRead))
            {
                if(fdSocket.fd_array[i] == sListen)        // (1)监听套节字接收到新连接
                {
                    if(fdSocket.fd_count < FD_SETSIZE)
                    {
                        sockaddr_in addrRemote;
                        int nAddrLen = sizeof(addrRemote);
                        SOCKET sNew = ::accept(sListen, (SOCKADDR*)&addrRemote, &nAddrLen);

                        FD_SET(sNew, &fdSocket);
                        printf("接收到连接(%s)\n", ::inet_ntoa(addrRemote.sin_addr));
                    }
                    else
                    {
                        printf(" Too much connections! \n");
                        continue;
                    }
                }
                else
                {
                    char szText[256];
                    int nRecv = ::recv(fdSocket.fd_array[i], szText, strlen(szText), 0);
                    if(nRecv > 0)                        // (2)可读
                    {
                        szText[nRecv] = '\0';
                        printf("接收到数据:%s \n", szText);
                    }
                    else                                // (3)连接关闭、重启或者中断
                    {
                        ::closesocket(fdSocket.fd_array[i]);
                        
                        printf("关闭\n");
                        FD_CLR(fdSocket.fd_array[i], &fdSocket);
                    }
                }
            }
        }
    }
    else
    {
        printf(" Failed select() \n");
        break;
    }
}

二.自己写了一个c#版本的socket的select方法使用

class Threadtcpserver
{
    private Socket server;
    public Threadtcpserver()
    {
        IPAddress local = IPAddress.Parse("127.0.0.1");
        IPEndPoint iep = new IPEndPoint(local, 4567);
        server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

        // 将套接字与本地终结点绑定    
        server.Bind(iep);

        //在本地13000端口号上进行监听    
        server.Listen(20);
        Console.WriteLine("等待客户机进行连接......");
        List<Socket> socketList = new List<Socket>();
        socketList.Add(server);

        while (true)
        {
            List<Socket> temp = socketList.ToList();
            Socket.Select(temp, null, null, 1000);
            int count = temp.Count;
            for (int i = 0; i < count; i++)
            {
                if (temp[i].Equals(server))
                {
                    Socket client = socketList[i].Accept();
                    socketList.Add(client);
                }
                else
                {
                    byte[] bytes = new byte[1024];
                    int len;
                    if ((len = temp[i].Receive(bytes)) > 0)
                    {
                        Console.WriteLine("收到数据:" + System.Text.Encoding.UTF8.GetString(bytes, 0, len));
                    }
                    else
                    {
                        temp[i].Close();
                        socketList.Remove(temp[i]);
                        Console.WriteLine("关闭");
                    }
                }
            }
        }
    }
}

测试:可以多次调用下面函数测试

public static void ClientTest()
{
    Socket client;
    byte[] buf = new byte[1024];
    string input;
    IPAddress local = IPAddress.Parse("127.0.0.1");
    IPEndPoint iep = new IPEndPoint(local, 4567);
    try
    {
        client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        client.Connect(iep);
    }
    catch (SocketException)
    {
        Console.WriteLine("无法连接到服务器!");
        return;
    }

    input = "test";
    client.Send(Encoding.ASCII.GetBytes(input));

    Console.WriteLine("断开与服务器的连接......");
    client.Close();
}