NIO核心概念和demo

RandomAccessFile aFile = new RandomAccessFile("data/nio-data.txt", "rw");
    FileChannel inChannel = aFile.getChannel();

    ByteBuffer buf = ByteBuffer.allocate(48);

    int bytesRead = inChannel.read(buf);
    while (bytesRead != -1) {

      System.out.println("Read " + bytesRead);
      buf.flip();

      while(buf.hasRemaining()){
          System.out.print((char) buf.get());
      }

      buf.clear();
      bytesRead = inChannel.read(buf);
    }
    aFile.close();

public class IoServer {
    private int port =8080;

    private Selector selector;
    private ByteBuffer buffer  = ByteBuffer.allocate(1024);

    public IoServer(int port){
        try {
            this.port = port;
            ServerSocketChannel server = ServerSocketChannel.open();
            server.bind(new InetSocketAddress(this.port));
            //兼容BIO
            server.configureBlocking(false);//设置之后为非阻塞

            selector = Selector.open();
            server.register(selector, SelectionKey.OP_ACCEPT);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void listen(){
        System.out.println("listen on " + this.port);
        while (true){
            try {
                selector.select();
                Set<SelectionKey> keys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = keys.iterator();
                while (iterator.hasNext()){
                    SelectionKey key = iterator.next();
                    iterator.remove();
                    process(key);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void process(SelectionKey key) throws IOException {
        if(key.isAcceptable()){
            ServerSocketChannel server = (ServerSocketChannel) key.channel();
            //非阻塞
            SocketChannel channel = server.accept();
            channel.configureBlocking(false);
            key = channel.register(selector, SelectionKey.OP_READ);
        }else if(key.isReadable()){
            //
        }else if (key.isWritable()){
            //
        }

    }

    public static void main(String[] args) {
        new IoServer(8080).listen();
    }