线程被阻止接受

Question

我正在使用java套接字制作多人游戏。我有这个代码

class GetServer
{
    private boolean connected = false;
    private Socket s = null;

    public Socket createSocket(String name)
    {
        return createSocket(name, 55902);
    }

    private synchronized Socket createSocket(String serverName, int port)
    {
        receivingThread.start();

        try
        {
            DatagramSocket ss = new DatagramSocket();
            ss.setBroadcast(true);
            byte[] b = serverName.getBytes();
            DatagramPacket p = new DatagramPacket(b, b.length);
            p.setAddress(InetAddress.getByAddress(new byte[] {(byte) 255, (byte) 255, (byte) 255, (byte) 255}));
            p.setPort(55902);

            while(!connected)
            {
                p.setData(b);
                ss.send(p);
            }

            return s;
        }
        catch(Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }

    public void cancel()
    {
        connected = true;
    }

    private Thread receivingThread = new Thread(new Runnable()
    {
        public void run() 
        {
            try
            {
                ServerSocket socket = new ServerSocket(55902);
                s = socket.accept();
                connected = true;
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }
    });
}

这是服务器用于连接到客户端的类。我们的想法是使用服务器的名称调用createSocket，它将广播其名称，直到客户端尝试使用接收线程连接到它。但是我也希望能够取消尝试连接到客户端。我添加了一个cancel方法，它使createSocket返回null，但receiveThread仍然在accept上被阻止。我将如何结束接收线程。