java的selector用法

对于java的NIO我不是很了解，正在学习中，以下是一个例子，可以读取telnet的输入

package com.test.nio;

import java.io.DataInputStream;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.spi.SelectorProvider;
import java.util.Iterator;
import java.util.Set;

public class TestSelector {

	/**
	 * @param args
	 * @throws Exception 
	 */
	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		
		Selector selector=SelectorProvider.provider().openSelector();
		ServerSocketChannel ssc= ServerSocketChannel.open();
		ssc.configureBlocking(false);
		ssc.socket().bind(new InetSocketAddress("127.0.0.1",7979));
		
		SelectionKey acceptKey=ssc.register(selector,SelectionKey.OP_ACCEPT);
		
		//System.out.println("通道就绪个数："+selector.select());
		int keysAdded=0;
		while((keysAdded=selector.select())>0)
		{
			Set readyKeys=selector.selectedKeys();
			Iterator i=readyKeys.iterator();
			
			while(i.hasNext())
			{
				SelectionKey sk=(SelectionKey) i.next();
				i.remove();
				ServerSocketChannel nextReady= (ServerSocketChannel) sk.channel();
				
				Socket s=nextReady.accept().socket();
				
				InputStream din=s.getInputStream();
				DataInputStream ds=new DataInputStream(din);
				String str=ds.readLine();
				while(str!=null)
				{
					System.out.println(str);
					str=ds.readLine();
				}
				
				
				
			}
		}
		
	}

}

使用telnet连接上，输入字符回车，可以在控制台上看到输出