Reactor模式和NIO

import java.io.IOException;
 java.net.InetAddress;
 java.net.InetSocketAddress;
 java.nio.channels.SelectionKey;
 java.nio.channels.Selector;
 java.nio.channels.ServerSocketChannel;
 java.util.Iterator;
 java.util.Set;

/**
 * 反应器模式 用于解决多用户访问并发问题
 * 
 * 举个例子：餐厅服务问题
 * 
 * 传统线程池做法：来一个客人(请求)去一个服务员(线程)
 * 反应器模式做法：当客人点菜的时候，服务员就可以去招呼其他客人了，等客人点好了菜，直接招呼一声：服务员
 * 
 * @author linxcool
 */
public class Reactor implements Runnable {
    final Selector selector;
     ServerSocketChannel serverSocketChannel;

    public Reactor(int port) throws IOException {
        selector = Selector.open();
        serverSocketChannel = ServerSocketChannel.open();
        InetSocketAddress inetSocketAddress = new InetSocketAddress(
                InetAddress.getLocalHost(),port);
        serverSocketChannel.socket().bind(inetSocketAddress);
        serverSocketChannel.configureBlocking(false);

        // 向selector注册该channel
        SelectionKey selectionKey = serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);

         利用selectionKey的attache功能绑定Acceptor 如果有事情，触发Acceptor
        selectionKey.attach(new Acceptor(this));
    }

    @Override
    void run() {
        try {
            while (!Thread.interrupted()) {
                selector.select();
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectionKeys.iterator();
                 Selector如果发现channel有OP_ACCEPT或READ事件发生，下列遍历就会进行。
                while (it.hasNext()) {
                     来一个事件 第一次触发一个accepter线程
                     以后触发SocketReadHandler
                    SelectionKey selectionKey = it.next();
                    dispatch(selectionKey);
                    selectionKeys.clear();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    
     * 运行Acceptor或SocketReadHandler
     * 
     * @param key
     */
     dispatch(SelectionKey key) {
        Runnable r = (Runnable) (key.attachment());
        if (r != null) {
            r.run();
        }
    }

}