package io.nio;

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.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;

/**
 * 服务端
 * @author zzh
 *
 */
public class NIOSocketServer {
	
	public static void main(String[] args) throws Exception {
		
		//创建选择器
		Selector selector = Selector.open();
		//创建一个socket通道
		ServerSocketChannel ssc = ServerSocketChannel.open();
		//通道为非阻塞
		ssc.configureBlocking(false);
		//绑定端口号
		ssc.bind(new InetSocketAddress("127.0.0.1", 8080));
		//关注接受到客户端连接的事件
		ssc.register(selector, SelectionKey.OP_ACCEPT);
		//用于字节和字符的转换
		Charset charset = Charset.forName("UTF-8");
		
		
		//select()阻塞到至少有一个通道在你注册的事件上就绪了
		while (selector.select() > 0) {
			// 一次处理selector上的每个选择的SelectionKey 
			Set<SelectionKey> selectedKeys = selector.selectedKeys();
			Iterator<SelectionKey> iterator = selectedKeys.iterator();
			while (iterator.hasNext()) {
				SelectionKey key = iterator.next();
				//客户端连接了
				if ((key.readyOps() & SelectionKey.OP_ACCEPT) == SelectionKey.OP_ACCEPT) {
					ServerSocketChannel ssChannel = (ServerSocketChannel) key.channel();
					SocketChannel sc = ssChannel.accept();
					sc.configureBlocking(false);
					sc.register(selector, SelectionKey.OP_READ);
					iterator.remove();
				//channal中有数据读
				} else if ((key.readyOps() & SelectionKey.OP_READ) == SelectionKey.OP_READ) {
					//创建缓冲区
					ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
					
					SocketChannel sc = (SocketChannel) key.channel();
					while (sc.read(byteBuffer) > 0) {//读数据到缓存
//						byteBuffer.clear();
//						int n = sc.read(byteBuffer);
//						if (n <= 0) {
//							break;
//						}
						//反转此缓冲区,调用此方法为一系列通道写入或相对获取 操作做好准备
						byteBuffer.flip();
						System.out.println("服务端读出了:" +  charset.decode(byteBuffer));
					}
					iterator.remove();
				}
			}
		}
	}

}
package io.nio;

import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Scanner;

/**
 * 客户端
 * @author zzh
 *
 */
public class NIOSocketClient {

	public static void main(String[] args) throws Exception {
		
		//Selector允许单线程处理多个 Channel
//		Selector selector = Selector.open();
		
		InetSocketAddress address = new InetSocketAddress("127.0.0.1", 8080);
		
		SocketChannel channel = SocketChannel.open(address);
		
		channel.configureBlocking(false);
		//监测读事件
//		channel.register(selector, SelectionKey.OP_READ);
		
		
		Charset charset = Charset.forName("UTF-8");
		
		Scanner scan = new Scanner(System.in); 
        while(scan.hasNextLine()) {  
            //读取键盘的输入  
            String line = scan.nextLine();  
            System.out.println("读入数据" + line);
            //将内容输出到SocketChanenel中 
            channel.write(charset.encode(line));  
        }
	}
}