java non blocking socket split big message...

Question

https://stackoverflow.com/questions/34254205/nio-channel-split-messages위 문제와 똑같은 상황이 발생하여 해결책을 찾고자 질문드립니다....java nio 패키지를 사용한 non block tcp 소켓 통신시 read 메서드 호출에서 클라이언트가 보낸 하나의 Message 를 수신하는 것이 아닌 여러개의 Message 한번에 읽어들입니다. 테스트를 위한 간단한 클래스 2개를 첨부합니다 package com.exam.nio; import lombok.Getter; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.nio.charset.Charset; import java.util.Iterator; import java.util.List; import java.util.Vector; @Getter public class Server { public static ServerSocketChannel serverSocketChannel; public static Selector selector; public static List connections = new Vector<>(); static { try { selector = Selector.open(); serverSocketChannel = ServerSocketChannel.open(); serverSocketChannel.configureBlocking(false); serverSocketChannel.bind(new InetSocketAddress(5001)); serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); } catch (IOException e) { e.printStackTrace(); if (serverSocketChannel.isOpen()) stopServer(); } } public static void main(String[] args) { Server server = new Server(); } public Server() { startServer(); } void startServer() { Thread thread = new Thread(() -> { try { while (true) { int keyCount = selector.select(); if (keyCount == 0) continue; Iterator iterator = selector.selectedKeys().iterator(); while (iterator.hasNext()) { SelectionKey selectionKey = iterator.next(); iterator.remove(); if (selectionKey.isAcceptable()) { accept(selectionKey); } else if (selectionKey.isReadable()) { Client client = (Client) selectionKey.attachment(); client.receive(selectionKey); } } } } catch (IOException e) { e.printStackTrace(); if (serverSocketChannel.isOpen()) stopServer(); } }); System.out.println("server start"); thread.start(); } static void stopServer() { try { Iterator iterator = connections.iterator(); while (iterator.hasNext()) { Client client = iterator.next(); client.socketChannel.close(); iterator.remove(); } if (serverSocketChannel != null && serverSocketChannel.isOpen()) { serverSocketChannel.close(); } if (selector != null && selector.isOpen()) { selector.close(); } System.out.println("server stop"); } catch (IOException e) { e.printStackTrace(); } } void accept(SelectionKey selectionKey) { try { ServerSocketChannel serverSocketChannel = (ServerSocketChannel) selectionKey.channel(); SocketChannel socketChannel = serverSocketChannel.accept(); String message = "accept! " + socketChannel.getRemoteAddress() + ", thread:" + Thread.currentThread().getName(); Client client = new Client(socketChannel); connections.add(client); System.out.println("connections size:" + connections.size() + ", " + message); } catch (IOException e) { e.printStackTrace(); if (serverSocketChannel.isOpen()) { stopServer(); } } } public class Client { public SocketChannel socketChannel; private String sendData; ByteBuffer byteBuffer = ByteBuffer.allocate(100); public Client(SocketChannel socketChannel) throws IOException { this.socketChannel = socketChannel; socketChannel.configureBlocking(false); SelectionKey selectionKey = socketChannel.register(Server.selector, SelectionKey.OP_READ); selectionKey.attach(this); } // from client receive data void receive(SelectionKey selectionKey) { try { byteBuffer.clear(); int byteCount = socketChannel.read(byteBuffer); if (byteCount == -1) { throw new IOException("byte count is -1"); } byteBuffer.flip(); // position to 0 Charset charset = Charset.forName("UTF-8"); String data = charset.decode(byteBuffer).toString(); System.out.println(socketChannel.getRemoteAddress() + ":" + Thread.currentThread().getName() + " - data:" + data); } catch (IOException e) { try { e.printStackTrace(); Server.connections.remove(this); String message = "connect error" + socketChannel.getRemoteAddress() + ":" + Thread.currentThread().getName(); System.out.println(message); socketChannel.close(); } catch (IOException ioException) { ioException.printStackTrace(); } } } } } package com.exam.nio; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.SocketChannel; import java.util.Iterator; import java.util.Set; public class ClientConnectMain { private static SocketChannel socketChannel; private static Selector selector; private static ByteBuffer messageBuffer; static { try { socketChannel = SocketChannel.open(); selector = Selector.open(); } catch (IOException e) { e.printStackTrace(); } } public static void main(String[] args) throws IOException { socketChannel.configureBlocking(false); socketChannel.register(selector, SelectionKey.OP_CONNECT); socketChannel.connect(new InetSocketAddress("localhost", 5001)); Runnable runnable = () -> { while (true) { try { int keyCount = selector.select(); if (keyCount == 0) continue; Set selectedKeys = selector.selectedKeys(); Iterator iterator = selectedKeys.iterator(); while (iterator.hasNext()) { SelectionKey selectionKey = iterator.next(); if (selectionKey.isConnectable()) { connect(selectionKey); } else if (selectionKey.isWritable()) { send(); } iterator.remove(); } } catch (Exception e) { System.out.println("client connect error"); stopClient(); break; } } }; new Thread(runnable).start(); } private static void stopClient() { System.out.println("stopClient invoked"); if (socketChannel.isOpen()) { if (socketChannel != null && socketChannel.isOpen()) { try { socketChannel.close(); } catch (IOException ioException) { ioException.printStackTrace(); } } } } private static void connect(SelectionKey selectionKey) { try { socketChannel.finishConnect(); System.out.println("[연결 완료: " + socketChannel.getRemoteAddress() + "]"); try { for (int i = 0; i < 100; i++) { String message = i + " message"; socketChannel.write(ByteBuffer.wrap(message.getBytes())); } System.out.println("[보내기 완료]"); socketChannel.close(); } catch (Exception e) { System.out.println("[서버 통신 안됨]"); stopClient(); } } catch (Exception e) { System.out.println("[서버 통신 안됨]"); if (socketChannel.isOpen()) { stopClient(); } } } private static void send() { } } 아래처럼 출력되네요... socketChannel.read(byteBuffer) 시에 여러개의 메세지를 한번이 읽어들이지 못하도록 할 수 있을까요? 사실 처리해야 하는건 바이트 배열을 특정 클래스로 변환하는 거라 위상황과 100% 똑같진 않지만 위 코드에서 발생하는 상황을 해결할 수 있으면 제 문제도 해결 가능할 것 같습니다... 읽어주신 모두에게 감사드립니다...

JohnMark · Accepted Answer

소켓으로 전송되는 데이터는 스트림입니다. 따로 메시지를 분리해서 보여주고 싶으시다면 메시지를 읽고, 특정 값을 통해 메시지를 분리해서 다루셔야합니다. 기본적으로 문자나 숫자를 보낸다고 하실때, 개행문자를 기준으로 메시지를 자릅니다.

Kkoji · Answer

var net &#61; require('net'); this.server &#61; new net.createServer(onClientConnected).listen(port); 아쉬운건 위와같은 자바스크립트에서 제공하는 소켓 채널은 별다른 작업 없이 메세지를 완벽히 분리해서 비동기 메서드로 던져주는 겁니다...자바에선 이를 해결할 수 있는 방법이 없을까요?.. byte 배열 하나하나씩 보고 파싱하려면 너무 어려울 것 같습니다ㅠ

java non blocking socket split big message...

2개의 답변

#socketchannel 목록