使用 Apache Mina 通过 UDP 将数据发送回客户端

Question

I am using Apache Mina to create a server to accept UDP Client requests. I have read the Official documentation provided by Apache Mina regarding UDP Server & UDP Client . However, I wished to know when the server receives a message, can I write back to the UDP Client using the same session(I know UDP is connectionless at Network Layer, however I can get the IP and PORT of the remote host at Application Layer) such that UDP Client receives a message. I know this is possible is TCP but am a little confused about UDP. I know this may not exactly be Java based but more Network Layer based question. Would appreciate if somebody could clear this for me.

Answer 1

@Override
    public void messageReceived(IoSession session, Object message) throws Exception {

            for (int i = 0; i < session.getService().getManagedSessions().values().toArray().length; i++) {

                IoSession aSession=(IoSession) session.getService().getManagedSessions().values().toArray()[i];
                aSession.write("Any Message");
            }



    }

Answer 2

Try this your handler class

@Override
public void messageReceived(IoSession session, Object message) throws Exception {
        // response every time get data 
        byte[] b = "Received".getBytes();
        final IoBuffer responsebuffer = IoBuffer.allocate(b.length);
        responsebuffer.put(b);
        responsebuffer.flip();
        session.write(responsebuffer);
        SocketAddress remoteAddress = session.getRemoteAddress();

        if (message instanceof IoBuffer) {
            IoBuffer buffer = (IoBuffer) message;
            final CharsetDecoder decoder = getCharsetDecoder(session);
            String receivedMsg = buffer.getString(decoder);
            String data = remoteAddress + " Received: " + receivedMsg;
            server.append(data);
        }

    }

Answer 3

I got the answer to the same and thought i would share.

UDP is connectionless however I can use the same session which I have in Apache Mina to write to the session. I tried it as a sample also and it worked.