我有一个简单的客户端 - 服务器应用程序，它的工作原理如下：服务器总是监听（在一个单独的线程中）客户端连接（它发送它希望服务器终止的进程名称）。
这是服务器：
private void btnStart_Click(object sender, EventArgs e)
{
_port = int.Parse(comboBoxPorts.SelectedItem.ToString());
_tcpListener = new TcpListener(_ipAddress, _port);
_keepRunning = true;
_listenerThread = new Thread(Listen);
HandleListenerThreadStartListenEvent += HandleListenerThreadStartedEventMethod;
ListenerThreadStartedEvent += HandleListenerThreadStartListenEvent;
_listenerThread.Start();
}
private void btnStop_Click(object sender, EventArgs e)
{
if (_tcpListener != null)
{
_keepRunning = false;
if (_tcpListener.Server.Connected)
{
_tcpListener.Server.Disconnect(true);
}
_tcpListener.Stop();
}
labelServerStatus.Text = "Server is stopped";
comboBoxPorts.Enabled = true;
btnStart.Enabled = true;
btnStop.Enabled = false;
}
private void Listen()
{
try
{
_tcpListener.Start();
OnListenerThreadStartListenEvent(); // just update the GUI
}
catch(Exception e)
{
MessageBox.Show("Port " + _port + " is NOT available." + Environment.NewLine +
"Please choose another one: " + e.Message);
return;
}
_keepRunning = true;
string ballonMessage = "Socket Server Running at " + _ipAddress + ", port: " + _port;
notifyIcon1.ShowBalloonTip(2000, "Simplex Listener", ballonMessage, ToolTipIcon.Info);
while (_keepRunning)
{
try
{
#region using AcceptSocket()
_clientSocket = _tcpListener.AcceptSocket();
string checkString = string.Empty;
IPAddress ipOfClient = ((IPEndPoint) _clientSocket.LocalEndPoint).Address;
notifyIcon1.ShowBalloonTip(2000, "Simplex Listener", "New client has connected from ip " + ipOfClient, ToolTipIcon.Info);
byte[] buffer = new byte[SIZE_OF_BUFFER];
int bytesReceived = _clientSocket.Receive(buffer);
// Concatenate chars as bytes to a received string.
for (int i = 0; i < bytesReceived; i++)
checkString += Convert.ToChar(buffer[i]);
//..... getting the name of process and kill it (and than open it...
RestartProcess(nameOfProcess, windowName, pathToExeFile);
// Client is waiting to know operation is complete- so send him some char...
ASCIIEncoding encoder = new ASCIIEncoding();
_clientSocket.Send(encoder.GetBytes("v"));
_clientSocket.Disconnect(true);
_clientSocket.Close();
#endregion
}
catch (Exception )
{
}
}
}
客户方：
public void RestartTheSoftwareInServerComputer(string ipOfServer, int portNumber)
{
TcpClient client = new TcpClient();
if (_serverEndPoint == null)
{
_serverEndPoint = new IPEndPoint(IPAddress.Parse(ipOfServer), portNumber);
}
client.Connect(_serverEndPoint);
// Send the command to the server:
NetworkStream clientStream = client.GetStream();
ASCIIEncoding encoder = new ASCIIEncoding();
byte[] buffer = encoder.GetBytes("....detailsOfProcess....");
clientStream.Write(buffer, 0, buffer.Length);
clientStream.Flush();
// Now, wait for the server's response [which means the process had been restart].
NetworkStream stream = client.GetStream();
byte[] bytes = new byte[5];
stream.Read(bytes, 0, 5);
string response = Encoding.UTF8.GetString(bytes, 0, 1);
if (response.Equals("x"))
{
throw new Exception("Failed to restart X software.");
}
stream.Close();
client.Close();
}
当我停止并重新启动服务器时（没有连接客户端时），一切正常。
问题是当服务器连接了一些客户端并重新启动时，客户端已断开连接，需要重新启动服务器。当我们再次点击“START SERVER”时，它将获得异常：
每个套接字地址只有一种用法（协议/网络地址/端口） 通常是允许的。
我应该如何关闭端口？
答案 0 :(得分：0)
退出服务器时，应调用_tcpListener.Stop（）来关闭服务器正在侦听的主套接字。
编辑：您也可以尝试在停止按钮单击中调用_listenerThread.Join（），等待侦听器线程完成，然后再启动下一个。
private void btnStop_Click(object sender, EventArgs e)
{
if (_tcpListener != null)
{
_keepRunning = false;
if (_tcpListener.Server.Connected)
{
_tcpListener.Server.Disconnect(true);
_tcpListener.Stop();
if (_clientSocket != null)
{
_clientSocket.Close();
_clientSocket = null;
}
_listenerThread.Join();
}
}
labelServerStatus.Text = "Server is stopped";
comboBoxPorts.Enabled = true;
btnStart.Enabled = true;
btnStop.Enabled = false;
}
编辑2：
这是一个与您的服务器类似的Windows窗体。我不需要客户端，只需在命令提示符下使用“telnet localhost 49152”来“假装”为客户端连接。
public partial class Form1 : Form
{
private TcpListener _tcpListener;
private bool _keepRunning;
private Thread _listenerThread;
private Socket _clientSocket;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
var address = IPAddress.Parse("127.0.0.1");
_tcpListener = new TcpListener(address, 49152);
_keepRunning = true;
_listenerThread = new Thread(Listen);
_listenerThread.Start();
button1.Enabled = false;
button2.Enabled = true;
}
private void Listen()
{
try
{
_tcpListener.Start();
}
catch (Exception e)
{
MessageBox.Show(e.Message);
return;
}
_keepRunning = true;
while (_keepRunning)
{
try
{
_clientSocket = _tcpListener.AcceptSocket();
var buffer = new byte[8192];
var bytesReceived = _clientSocket.Receive(buffer);
var checkString = String.Empty;
if (_keepRunning)
{
// bytesReceived can be 0 if the remote socket disconnected
if (bytesReceived > 0)
{
checkString = Encoding.ASCII.GetString(buffer, 0, bytesReceived);
// Client is waiting to know operation is complete- so send him some char...
var encoder = new ASCIIEncoding();
_clientSocket.Send(encoder.GetBytes("v"));
}
if (_clientSocket.Connected) _clientSocket.Disconnect(true);
}
_clientSocket.Close();
}
catch (Exception ex)
{
// really should do something with these exceptions
}
}
}
private void button2_Click(object sender, EventArgs e)
{
if (_tcpListener != null)
{
_keepRunning = false;
if (_tcpListener.Server.Connected)
{
_tcpListener.Server.Disconnect(true);
}
_tcpListener.Stop();
if (_clientSocket != null)
{
_clientSocket.Close();
_clientSocket = null;
}
_listenerThread.Join();
}
button1.Enabled = true;
button2.Enabled = false;
}
}
此代码存在许多问题，例如在线程之间共享变量等，但在我的机器上，Join似乎没有阻塞任何时间长度。 _keepRunning的问题在于，在某些系统上，一个线程可能无法看到从true变为false的变化，因为它被优化或缓存。你应该使用某种形式的线程同步，使它变得易失，或将它包装在锁等中。我建议你阅读here。我也建议您也阅读套接字，或者如果其他评论者提到过，如果您对了解套接字和线程的所有特性不感兴趣，也许您应该寻找一个更高级别的库来隐藏这一切？