import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.util.Iterator;
import 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 {public final Selector selector;public final 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channelSelectionKey selectionKey = serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);// 利用selectionKey的attache功能绑定Acceptor 如果有事情，触发AcceptorselectionKey.attach(new Acceptor(this));}@Overridepublic 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SocketReadHandlerSelectionKey selectionKey = it.next();dispatch(selectionKey);selectionKeys.clear();}}} catch (IOException e) {e.printStackTrace();}}/*** 运行Acceptor或SocketReadHandler* * @param key*/void dispatch(SelectionKey key) {Runnable r = (Runnable) (key.attachment());if (r != null) {r.run();}}}

import java.io.IOException;
import java.nio.channels.SocketChannel;public class Acceptor implements Runnable {private Reactor reactor;public Acceptor(Reactor reactor) {this.reactor = reactor;}@Overridepublic void run() {try {SocketChannel socketChannel = reactor.serverSocketChannel.accept();if (socketChannel != null)// 调用Handler来处理channelnew SocketReadHandler(reactor.selector, socketChannel);} catch (IOException e) {e.printStackTrace();}}
}

public class SocketReadHandler implements Runnable {private SocketChannel socketChannel;public SocketReadHandler(Selector selector, SocketChannel socketChannel)throws IOException {this.socketChannel = socketChannel;socketChannel.configureBlocking(false);SelectionKey selectionKey = socketChannel.register(selector, 0);// 将SelectionKey绑定为本Handler 下一步有事件触发时，将调用本类的run方法。// 参看dispatch(SelectionKey key)selectionKey.attach(this);// 同时将SelectionKey标记为可读，以便读取。
        selectionKey.interestOps(SelectionKey.OP_READ);selector.wakeup();}/*** 处理读取数据*/@Overridepublic void run() {ByteBuffer inputBuffer = ByteBuffer.allocate(1024);inputBuffer.clear();try {socketChannel.read(inputBuffer);// 激活线程池 处理这些request// requestHandle(new Request(socket,btt));} catch (IOException e) {e.printStackTrace();}}
}