Channel selector

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;
/*from   ja va2s .  c o  m*/
public class MainClass {

  private static byte[] data = new byte[255];

  public static void main(String[] args) throws IOException {
    for (int i = 0; i < data.length; i++)
      data[i] = (byte) i;

    ServerSocketChannel server = ServerSocketChannel.open();
    server.configureBlocking(false);

    server.socket().bind(new InetSocketAddress(9000));
    Selector selector = Selector.open();
    server.register(selector, SelectionKey.OP_ACCEPT);

    while (true) {
      selector.select();
      Set readyKeys = selector.selectedKeys();
      Iterator iterator = readyKeys.iterator();
      while (iterator.hasNext()) {
        SelectionKey key = (SelectionKey) iterator.next();
        iterator.remove();
        if (key.isAcceptable()) {
          SocketChannel client = server.accept();
          System.out.println("Accepted connection from " + client);
          client.configureBlocking(false);
          ByteBuffer source = ByteBuffer.wrap(data);
          SelectionKey key2 = client.register(selector, SelectionKey.OP_WRITE);
          key2.attach(source);
        } else if (key.isWritable()) {
          SocketChannel client = (SocketChannel) key.channel();
          ByteBuffer output = (ByteBuffer) key.attachment();
          if (!output.hasRemaining()) {
            output.rewind();
          }
          client.write(output);
        }
        key.channel().close();
      }
    }
  }
}

import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
//  ja v  a2 s  .c o m
public class Main {
  public static void main(String[] argv) throws Exception {
    Selector selector = Selector.open();

    ServerSocketChannel ssChannel1 = ServerSocketChannel.open();
    ssChannel1.configureBlocking(false);
    ssChannel1.socket().bind(new InetSocketAddress(80));

    ServerSocketChannel ssChannel2 = ServerSocketChannel.open();
    ssChannel2.configureBlocking(false);
    ssChannel2.socket().bind(new InetSocketAddress(81));

    ssChannel1.register(selector, SelectionKey.OP_ACCEPT);
    ssChannel2.register(selector, SelectionKey.OP_ACCEPT);

    while (true) {
      selector.select();
      Iterator it = selector.selectedKeys().iterator();
      while (it.hasNext()) {
        SelectionKey selKey = (SelectionKey) it.next();
        it.remove();

        if (selKey.isAcceptable()) {
          ServerSocketChannel ssChannel = (ServerSocketChannel) selKey.channel();
          SocketChannel sc = ssChannel.accept();
          ByteBuffer buf = ByteBuffer.allocate(100);
          int numBytesRead = sc.read(buf);
      
          if (numBytesRead == -1) {
              sc.close();
          } else {
              // Read the bytes from the buffer
          }
          int numBytesWritten = sc.write(buf);
        }
      }
    }
  }
}