NIO的简单Demo

package jesse.test1;

import java.io.IOException;

import java.net.InetAddress;

import java.net.InetSocketAddress;

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;

public class NIOServer extends Thread{

    @Override

    public void run(){

        try {

            // 1，创建Selector 和 Channel

            Selector selector = Selector.open();

            ServerSocketChannel serverSocket = ServerSocketChannel.open();

            //

            serverSocket.bind(new InetSocketAddress(InetAddress.getLocalHost(), 8888));

            serverSocket.configureBlocking(false);

            // 注册到Selector，并说明关注点

            serverSocket.register(selector, SelectionKey.OP_ACCEPT);

            while(true){

                //阻塞等待就绪的Channel

                selector.select();

                Set<SelectionKey> selectedKeys = selector.selectedKeys();

                Iterator<SelectionKey> iter = selectedKeys.iterator();

                while(iter.hasNext()){

                    SelectionKey key = iter.next();

                    // 生产中一般会额外进行就绪状态检查

                    sayHelloWorld((ServerSocketChannel) key.channel());

                    iter.remove();

                }

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    private void sayHelloWorld(ServerSocketChannel server){

        try {

            SocketChannel client = server.accept();

            client.write(Charset.defaultCharset().encode("hello World."));

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    public static void main(String[] args) {

        /*NIOServer server = new NIOServer();

        server.start();

        try {

            Socket client = new Socket(InetAddress.getLocalHost(), 8888);

            BufferedReader bufferReader = new BufferedReader(new InputStreamReader(client.getInputStream()));

            System.out.println(bufferReader.readLine());

        } catch (IOException e) {

            e.printStackTrace();

        }*/

        System.out.println("hello world");

        ThreadGroup group = Thread.currentThread().getThreadGroup();

        ThreadGroup topGroup = group;

        while (group != null) {

        topGroup = group;

        group = group.getParent();

        }

        int nowThreads = topGroup.activeCount();

        Thread[] lstThreads = new Thread[nowThreads];

        topGroup.enumerate(lstThreads);

        for (int i = 0; i < nowThreads; i++) {

        System.out.println("线程number：" + i + " = " + lstThreads[i].getName());

        }

    }

}

/**

 * 1、通过Selector.open 创建Selector，类似调度员

 * 2、创建一个ServerSocketChannel，并且注册到Selector上，指定SelectionKey.OP_ACCEPT,接收新的连接请求

 * 3、Selector阻塞在select请求，当有Channel发生接入请求，会被唤醒

 * 4、通过SocketChannel和Buffer进行数据操作，

 */