NIO实现的客户端和服务端

学习NIO通信笔记   可直接执行

public class NIOServer {

    private static int BUFF_SIZE=1024;
    private static int TIME_OUT = 2000;

    public static void main(String[] args) throws IOException {

        Selector selector = Selector.open();
        ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();
        serverSocketChannel.bind(new InetSocketAddress(10083));
        serverSocketChannel.configureBlocking(false);
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        TCPProtocol protocol = new EchoSelectorProtocol(BUFF_SIZE);
        while (true) {
            if(selector.select(TIME_OUT)==0){
                //在等待信道准备的同时，也可以异步地执行其他任务，  这里打印*
                System.out.print("*");
                continue;
            }
            Iterator<SelectionKey> keyIter = selector.selectedKeys().iterator();
            while (keyIter.hasNext()) {
                SelectionKey key = keyIter.next();
                //如果服务端信道感兴趣的I/O操作为accept
                if (key.isAcceptable()){
                    protocol.handleAccept(key);
                }
                //如果客户端信道感兴趣的I/O操作为read
                if (key.isReadable()){
                    protocol.handleRead(key);
                }
                //如果该键值有效，并且其对应的客户端信道感兴趣的I/O操作为write
                if (key.isValid() && key.isWritable()) {
                    protocol.handleWrite(key);
                }
                //这里需要手动从键集中移除当前的key
                keyIter.remove();
            }

        }
    }
}

public class NIOClient {

    public static Selector selector;
    public static SocketChannel clntChan;

    static {
        try {
            selector = Selector.open();
            clntChan = SocketChannel.open();
            clntChan.configureBlocking(false);
            clntChan.connect(new InetSocketAddress("localhost", 10083));
            clntChan.register(selector, SelectionKey.OP_READ);
            while (!clntChan.finishConnect()){

            }
            System.out.println("已连接！");
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {
            SocketChannel socketChannel = NIOClient.clntChan;
            ByteBuffer byteBuffer = ByteBuffer.allocate(256);
            new Avca(selector,socketChannel).start();
            while (true){
                Scanner scanner = new Scanner(System.in);
                String word = scanner.nextLine();
                byteBuffer.put(word.getBytes());
                byteBuffer.flip();
                socketChannel.write(byteBuffer);
                byteBuffer.clear();
            }
    }

    static class Avca extends Thread{
        private Selector selector;
        private SocketChannel clntChan;

       public Avca(Selector selector,SocketChannel clntChan){
            this.selector = selector;
            this.clntChan = clntChan;
       }

        @Override
        public void run(){
            try {
                while (true){
                    selector.select();
                    Set<SelectionKey> keys = selector.selectedKeys();
                    Iterator<SelectionKey> keyIterator = keys.iterator();
                    ByteBuffer byteBuffer = ByteBuffer.allocate(256);
                    while (keyIterator.hasNext()){
                        SelectionKey selectionKey = keyIterator.next();
                        if (selectionKey.isValid()){
                            if (selectionKey.isReadable()){
                                SocketChannel socketChannel = (SocketChannel)selectionKey.channel();
                                socketChannel.read(byteBuffer);
                                byteBuffer.flip();
                                byte[] bytes = new byte[byteBuffer.remaining()];
                                byteBuffer.get(bytes);
                                System.out.println(new String(bytes));
                                byteBuffer.clear();
                            }
                        }
                    }
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }

}