Java NIO系列教程（六） Selector http://ifeve.com/selectors/

NIOSelector.java

Selector selector = Selector.open();
channel.configureBlocking(false);
SelectionKey key = channel.register(selector, SelectionKey.OP_READ);
while(true) {
  int readyChannels = selector.select();
  if(readyChannels == 0) continue;
  Set selectedKeys = selector.selectedKeys();
  Iterator keyIterator = selectedKeys.iterator();
  while(keyIterator.hasNext()) {
    SelectionKey key = keyIterator.next();
    if(key.isAcceptable()) {
        // a connection was accepted by a ServerSocketChannel.
    } else if (key.isConnectable()) {
        // a connection was established with a remote server.
    } else if (key.isReadable()) {
        // a channel is ready for reading
    } else if (key.isWritable()) {
        // a channel is ready for writing
    }
    keyIterator.remove();
    // 注意每次迭代末尾的keyIterator.remove()调用。
    // Selector不会自己从已选择键集中移除SelectionKey实例。
    // 必须在处理完通道时自己移除。下次该通道变成就绪时，Selector会再次将其放入已选择键集中。
  }
}