Java NIO-在服务器端注销客户端连接

Question

I am writing a simple NIO server using Selectors and NIO channels. Every time I have an incoming connection, I register it with the Selector using the following code:

// accept connection
 SocketChannel client = server.accept();
 System.out.println("Accepting connection from " + client.socket().getLocalSocketAddress());

 client.configureBlocking(false);
 client.socket().setTcpNoDelay(true);
 client.register(selector, SelectionKey.OP_READ);

On the client side, since I have only one socketChannel, it is easy to simply close the channel and de-register with the selector. On the erver side, however, all I'm doing is await writes from ANY client that ever connected (potentially thousands). I sthere a way to detect that the client has disconnected on the server side? It seems that the selector will get very inefficient after eg 10K connections, most of which would probably be dead after a short while..

Answer 1

When the client disconnects, the server will get an OP_READ event for the channel, and read() will return -1. When this happens, close the channel.

NB You only have to close the channel. Cancelling the key, deregistration etc, happens automatically.