以下非同步(異步)示例全部使用tcp協議.
1.在編寫服務端及客戶端代碼之前,先編寫一個共用的用於保存接收信息的類:
//接收到的數據 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();
}
2.服務端示例:
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。
public class AsynchronousSocketListener
{
// 定義線程標識
public static ManualResetEvent allDone = new ManualResetEvent(false);
public AsynchronousSocketListener()
{
}
public static void StartListening()
{
// 暫存接收數據
byte[] bytes = new Byte[1024];
// 建立本地端口
// The DNS name of the computer running the listener is "host.contoso.com".
IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
// 建立socket
Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// Bind本地端口並偵聽連接
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// 開始偵聽
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(new AsyncCallback(AcceptCallback), listener);
// 暫停直到有新的連接 Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine(" Press ENTER to continue...");
Console.Read();
}
public static void AcceptCallback(IAsyncResult ar)
{
// 標識主線程繼續
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));
// 檢查是否含有文件尾標識,如果沒有,繼續讀取數據
content = state.sb.ToString();
if (content.IndexOf("<EOF>") > -1)
{
// 顯示接收到的數據
Console.WriteLine("Read {0} bytes from socket. Data : {1}", content.Length, content);
// 發送數據 Echo the data back to the client.
Send(handler, content);
}
else
{
// 繼續接收數據
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), state);
}
}
}
private static void Send(Socket handler, String data)
{
// 將字符串轉化為字節數組
byte[] byteData = Encoding.ASCII.GetBytes(data);
// 開始發送數據
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;
// 完成發送數據
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;
}
}
3.客戶端示例:
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。
public class AsynchronousClient
{
// 定義遠程端口
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);
// 接收到的數據 The response from the remote device.
private static String response = String.Empty;
private static void StartClient()
{
// 連接遠程設備
try
{
// 建立遠程端口
IPHostEntry ipHostInfo = Dns.GetHostEntry("host.contoso.com");
IPAddress ipAddress = ipHostInfo.AddressList[0];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
// 建立socket
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// 連接遠程端口
client.BeginConnect(remoteEP, new AsyncCallback(ConnectCallback), client);
connectDone.WaitOne();
// 發送數據
Send(client, "This is a test<EOF>");
sendDone.WaitOne();
// 接收數據
Receive(client);
receiveDone.WaitOne();
// 顯示接收到的數據
Console.WriteLine("Response received : {0}", response);
// 關閉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;
// 完成連接
client.EndConnect(ar);
Console.WriteLine("Socket connected to {0}",
client.RemoteEndPoint.ToString());
// 標識連接完成
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;
// 開始接收數據
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));
// 繼續接收數據
client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state);
}
else
{
//數據接收完後,顯示數據.
if (state.sb.Length > 1)
{
response = state.sb.ToString();
}
//標識數據接收完畢
receiveDone.Set();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private static void Send(Socket client, String data)
{
//將字符串轉化為ascii字節數組
byte[] byteData = Encoding.ASCII.GetBytes(data);
// 開始發送數據
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;
// 完成發送數據
int bytesSent = client.EndSend(ar);
Console.WriteLine("Sent {0} bytes to server.", bytesSent);
// 標識數據發送完畢
sendDone.Set();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public static int Main(String[] args)
{
StartClient();
return 0;
}
}
參考文獻: 1. http://www.jb51.net/html/200703/85/8049.htm