关于MSDN上的同步服务器_客户端套接字示例的疑问

Question

异步服务器套接字示例  下面的示例程序创建一个接收来自客户端的连接请求的服务器。该服务器是用异步套接字生成的，因此在等待来自客户端的连接时不挂起服务器应用程序的执行。该应用程序接收来自客户端的字符串，在控制台显示该字符串，然后将该字符串回显到客户端。来自客户端的字符串必须包含字符串“<EOF>”，以发出表示消息结尾的信号。[C#]
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;// State object for reading client data asynchronously
public class StateObject {
    // Client  socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 1024;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
// Received data string.
    public StringBuilder sb = new StringBuilder();  
}public class AsynchronousSocketListener {
    
    // Incoming data from client.
    public static string data = null;    // Thread signal.
    public static ManualResetEvent allDone = new ManualResetEvent(false);    public AsynchronousSocketListener() {
    }    public static void StartListening() {
        // Data buffer for incoming data.
        byte[] bytes = new Byte[1024];        // Establish the local endpoint for the socket.
        // The DNS name of the computer
        // running the listener is "host.contoso.com".
        IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
        IPAddress ipAddress = ipHostInfo.AddressList[0];
        IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);        // Create a TCP/IP socket.
        Socket listener = new Socket(AddressFamily.InterNetwork,
            SocketType.Stream, ProtocolType.Tcp );        // Bind the socket to the local endpoint and listen for incoming connections.
        try {
            listener.Bind(localEndPoint);
            listener.Listen(100);            while (true) {
                // Set the event to nonsignaled state.
                allDone.Reset();                // Start an asynchronous socket to listen for connections.
                Console.WriteLine("Waiting for a connection...");
                listener.BeginAccept( 
                    new AsyncCallback(AcceptCallback),
                    listener );                // Wait until a connection is made before continuing.
                allDone.WaitOne();
            }        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }        Console.WriteLine("\nPress ENTER to continue...");
        Console.Read();
        
    }    public static void AcceptCallback(IAsyncResult ar) {
        // Signal the main thread to continue.
        allDone.Set();        // Get the socket that handles the client request.
        Socket listener = (Socket) ar.AsyncState;
        Socket handler = listener.EndAccept(ar);        // Create the state object.
        StateObject state = new StateObject();
        state.workSocket = handler;
        handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
            new AsyncCallback(ReadCallback), state);
    }    public static void ReadCallback(IAsyncResult ar) {
        String content = String.Empty;
        
        // Retrieve the state object and the handler socket
        // from the asynchronous state object.
        StateObject state = (StateObject) ar.AsyncState;
        Socket handler = state.workSocket;        // Read data from the client socket. 
        int bytesRead = handler.EndReceive(ar);        if (bytesRead > 0) {
            // There  might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(
                state.buffer,0,bytesRead));            // Check for end-of-file tag. If it is not there, read 
            // more data.
            content = state.sb.ToString();
            if (content.IndexOf("<EOF>") > -1) {
                // All the data has been read from the 
                // client. Display it on the console.
                Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
                    content.Length, content );
                // Echo the data back to the client.
                Send(handler, content);
            } else {
                // Not all data received. Get more.
                handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReadCallback), state);
            }
        }
    }
    
    private static void Send(Socket handler, String data) {
        // Convert the string data to byte data using ASCII encoding.
        byte[] byteData = Encoding.ASCII.GetBytes(data);        // Begin sending the data to the remote device.
        handler.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), handler);
    }    private static void SendCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket handler = (Socket) ar.AsyncState;            // Complete sending the data to the remote device.
            int bytesSent = handler.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to client.", bytesSent);            handler.Shutdown(SocketShutdown.Both);
            handler.Close();        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }
    public static int Main(String[] args) {
        StartListening();
        return 0;
    }
}

Answer 1

异步客户端套接字示例  下面的示例程序创建一个连接到服务器的客户端。该客户端是用异步套接字生成的，因此在等待服务器返回响应时不挂起客户端应用程序的执行。该应用程序将字符串发送到服务器，然后在控制台显示该服务器返回的字符串。[C#]
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Text;// State object for receiving data from remote device.
public class StateObject {
    // Client socket.
    public Socket workSocket = null;
    // Size of receive buffer.
    public const int BufferSize = 256;
    // Receive buffer.
    public byte[] buffer = new byte[BufferSize];
    // Received data string.
    public StringBuilder sb = new StringBuilder();
}public class AsynchronousClient {
    // The port number for the remote device.
    private const int port = 11000;    // ManualResetEvent instances signal completion.
    private static ManualResetEvent connectDone = 
        new ManualResetEvent(false);
    private static ManualResetEvent sendDone = 
        new ManualResetEvent(false);
    private static ManualResetEvent receiveDone = 
        new ManualResetEvent(false);    // The response from the remote device.
    private static String response = String.Empty;    private static void StartClient() {
        // Connect to a remote device.
        try {
            // Establish the remote endpoint for the socket.
            // The name of the 
            // remote device is "host.contoso.com".
            IPHostEntry ipHostInfo = Dns.Resolve("host.contoso.com");
            IPAddress ipAddress = ipHostInfo.AddressList[0];
            IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);            // Create a TCP/IP socket.
            Socket client = new Socket(AddressFamily.InterNetwork,
                SocketType.Stream, ProtocolType.Tcp);            // Connect to the remote endpoint.
            client.BeginConnect( remoteEP, 
                new AsyncCallback(ConnectCallback), client);
            connectDone.WaitOne();            // Send test data to the remote device.
            Send(client,"This is a test<EOF>");
            sendDone.WaitOne();            // Receive the response from the remote device.
            Receive(client);
            receiveDone.WaitOne();            // Write the response to the console.
            Console.WriteLine("Response received : {0}", response);            // Release the socket.
            client.Shutdown(SocketShutdown.Both);
            client.Close();
            
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }    private static void ConnectCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket client = (Socket) ar.AsyncState;            // Complete the connection.
            client.EndConnect(ar);            Console.WriteLine("Socket connected to {0}",
                client.RemoteEndPoint.ToString());            // Signal that the connection has been made.
            connectDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }    private static void Receive(Socket client) {
        try {
            // Create the state object.
            StateObject state = new StateObject();
            state.workSocket = client;            // Begin receiving the data from the remote device.
            client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
                new AsyncCallback(ReceiveCallback), state);
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }    private static void ReceiveCallback( IAsyncResult ar ) {
        try {
            // Retrieve the state object and the client socket 
            // from the asynchronous state object.
            StateObject state = (StateObject) ar.AsyncState;
            Socket client = state.workSocket;            // Read data from the remote device.
            int bytesRead = client.EndReceive(ar);            if (bytesRead > 0) {
                // There might be more data, so store the data received so far.
            state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead));                // Get the rest of the data.
                client.BeginReceive(state.buffer,0,StateObject.BufferSize,0,
                    new AsyncCallback(ReceiveCallback), state);
            } else {
                // All the data has arrived; put it in response.
                if (state.sb.Length > 1) {
                    response = state.sb.ToString();
                }
                // Signal that all bytes have been received.
                receiveDone.Set();
            }
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }    private static void Send(Socket client, String data) {
        // Convert the string data to byte data using ASCII encoding.
        byte[] byteData = Encoding.ASCII.GetBytes(data);        // Begin sending the data to the remote device.
        client.BeginSend(byteData, 0, byteData.Length, 0,
            new AsyncCallback(SendCallback), client);
    }    private static void SendCallback(IAsyncResult ar) {
        try {
            // Retrieve the socket from the state object.
            Socket client = (Socket) ar.AsyncState;            // Complete sending the data to the remote device.
            int bytesSent = client.EndSend(ar);
            Console.WriteLine("Sent {0} bytes to server.", bytesSent);            // Signal that all bytes have been sent.
            sendDone.Set();
        } catch (Exception e) {
            Console.WriteLine(e.ToString());
        }
    }
    
    public static int Main(String[] args) {
        StartClient();
        return 0;
    }
}上面的代码,学.NET的前辈应该都看过吧,我调试的时候,把服务器上
ReadCallback方法中高度SEND方法的地方
改成content = Console.ReadLine();
,发现如果是自己的机器上开多个CLIENT的时候
服务器等待我输入数据时会,像排队一样
第一次输入的资料会传入第一个开启的CLIENT
第二次输入的资料会传入第二个开启的CLIENT
依次这样...这样的话,各个CLIENT的数据要等待其它人结束,还算是异步吗?

Answer 2

哎....我提的问题 就这么没水准吗?MSDN上的代码 大家都应该看过吧...怎么说一声 也不干..

Answer 3

newnan(神出鬼没)  谢谢支持...结贴..哎..