AsynchronousSocketChannel #read永远不会完成。

Question

I'm experimenting with NIO2 and running into an issue.

Here's the code I'm using:

ByteBuffer buffer = ByteBuffer.allocate(DEFAULT_BUFFER_SIZE);
    channel.read(buffer, null, new CompletionHandler<Integer, Object>() {
        @Override
        public void completed(Integer result, Object attachment) {
            Packet packet = new Packet(buffer.getInt(), buffer);
            PacketHandler handler = PacketHandler.forOpcode(packet.getOpcode());
            if(!Objects.isNull(handler)) {
                handler.handle(channel, packet);
            } else {
                System.out.println("Unexpected opcode received from client. Opcode: " + packet.getOpcode());
            }
        }

        @Override
        public void failed(Throwable exc, Object attachment) {
            System.out.println("DEBUG A");
            exc.printStackTrace();
        }
    });

The issue is that no-matter what I send the server, it never completes. For testing purposes I have a very flat-format login packet set up and I'm sending this data through the client:

    ByteBuffer buffer = ByteBuffer.allocate(28);
    buffer.putInt(1); //opcode
    ByteBufferUtils.putString(buffer, "admin");
    ByteBufferUtils.putString(buffer, "admin");
    channel.write(buffer);

Even though the client writes the data, the server never finishes reading this. I've also made sure that (DEFAULT_BUFFER_SIZE) was equal to the sent buffer size to see if that was the issue, but there were still not any changes in functionality.

Whenever I disconnect the client (Currently using a thread to keep it alive, for absolutely no reason) I get the following print stack trace from #failed

java.io.IOException: The specified network name is no longer available.
at sun.nio.ch.Iocp.translateErrorToIOException(Iocp.java:309)
at sun.nio.ch.Iocp.access$700(Iocp.java:46)
at sun.nio.ch.Iocp$EventHandlerTask.run(Iocp.java:399)
at java.lang.Thread.run(Thread.java:745)

Answer 1

You aren't sending anything. You need to flip() the buffer before calling write(), and compact() it afterwards.