使用select（）服务多个通道

 

import java.net.InetSocketAddress;

import java.net.ServerSocket;
/* 
 来自 
*时代Java公众号*/

import java.nio.ByteBuffer;

import java.nio.channels.SelectableChannel;

import java.nio.channels.SelectionKey;

import java.nio.channels.Selector;

import java.nio.channels.ServerSocketChannel;

import java.nio.channels.SocketChannel;

import java.util.Iterator;


public class Main {/**来 自 nowjava.com - 时代Java**/

  public static void main(String[] argv) throws Exception {

    int port = 5555;

    System.out.println("Listening on port " + port);

    ServerSocketChannel serverChannel = ServerSocketChannel.open();

    ServerSocket serverSocket = serverChannel.socket();

    Selector selector = Selector.open();

    serverSocket.bind(new InetSocketAddress(port));

    serverChannel.configureBlocking(false);

    serverChannel.register(selector, SelectionKey.OP_ACCEPT);

    while (true) {

      int n = selector.select();

      if (n == 0) {

        continue; // nothing to do

      }

      Iterator it = selector.selectedKeys().iterator();

      while (it.hasNext()) {

        SelectionKey key = (SelectionKey) it.next();

        if (key.isAcceptable()) {

          ServerSocketChannel server = (ServerSocketChannel) key.channel();

          SocketChannel channel = server.accept();

          registerChannel(selector, channel, SelectionKey.OP_READ);

          channel.write(ByteBuffer.wrap("Hi there!\r\n".getBytes()));

        }

        if (key.isReadable()) {

          readDataFromSocket(key);

        }

        it.remove();

      }

    }

  }

  protected static void registerChannel(Selector selector, SelectableChannel channel,

      int ops) throws Exception {

    if (channel == null) {

      return; // could happen

    }

    channel.configureBlocking(false);

    channel.register(selector, ops);

  }

  protected static void readDataFromSocket(SelectionKey key) throws Exception {

    SocketChannel socketChannel = (SocketChannel) key.channel();