JAVA NIO 基础学习

package com.hrd.netty.demo.jnio;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
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;

/**
 * Created by hurd on 2016/1/26.
 */
public class NioServerListener extends Thread {

    protected Selector selector;
    protected SocketChannel socketChannel;

    public NioServerListener(Selector selector){
        this.selector = selector;
    }

    @Override
    public void run(){

        try {
            //while循环监听事件
            while(true){
                //阻塞
                selector.select();
                //获取选择器中已经就绪的SelectionKey集合
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                //遍历
                while (iterator.hasNext()){
                    SelectionKey key = iterator.next();
                    //删除
                    iterator.remove();
                    //接受连接就绪事件
                    if(key.isAcceptable()){
                        ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
                        socketChannel = ssc.accept();
                        //套接字通道设置为非阻塞模式
                        socketChannel.configureBlocking(false);
                        //向socket通道 注册读就绪事件
                        socketChannel.register(selector, SelectionKey.OP_READ);
                    }else if(key.isReadable()){
                        //SocketChannel socketChannel = (SocketChannel) key.channel();
                        ByteBuffer byteBuffer = ByteBuffer.allocate(100);
                        int len = socketChannel.read(byteBuffer);
                         /*StringBuffer  dataBuffer= new StringBuffer();
                        while( -1 != len){
                            //将写模式变为读模式
                            byteBuffer.flip();
                            CharBuffer charBuffer = byteBuffer.asCharBuffer();
                            dataBuffer.append(charBuffer.array());
                            byteBuffer.clear();
                            len = socketChannel.read(byteBuffer);
                        }*/
                        byteBuffer.flip();
                        //读取完毕
                        if(byteBuffer.limit()>0){
                            System.out.println("来自服务端消息:" + new String(byteBuffer.array()).trim());
                        }
                    }else if(key.isWritable()){
                        //暂时还没想明白这个写就绪事件干嘛用的。。。
                        System.out.println("暂不处理");
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) throws IOException {

        //打开一个 ServerSocketChannel实例 并设置为false
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.configureBlocking(false);
        //绑定ip +端口
        serverSocketChannel.socket().bind(new InetSocketAddress("127.0.0.1",1024));
        //打开一个选择器
        Selector selector = Selector.open();
        //向 serverSocketChannel 注册 接收就绪事件
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        //开启线程进行监听
        NioServerListener listener = new NioServerListener (selector);
        listener.start();
        //进行控制太输入 写事件 进行通讯
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            //java IO 阻塞读取数据
            String data = bufferedReader.readLine();
            if("exit".equals(data)){
                if(null != listener.socketChannel){
                    listener.socketChannel.close();
                }
                System.out.println("主线程关闭.....");
                System.exit(0);
            }
            ByteBuffer buffer = ByteBuffer.wrap(data.getBytes());
            listener.socketChannel.write(buffer);
        }
    }
}

客户端 监听    

package com.hrd.netty.demo.jnio;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

/**
 * Created by hurd on 2016/1/26.
 */
public class NioClientListener extends Thread {

    public Selector selector;
    public SocketChannel socketChannel;

    public NioClientListener(Selector selector){
        this.selector = selector;
    }

    @Override
    public void run(){

        try {
            //while循环监听事件
            while(true){
                //阻塞
                selector.select();
                //获取选择器中已经就绪的SelectionKey集合
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                //遍历
                while (iterator.hasNext()){
                    SelectionKey key = iterator.next();
                    //删除
                    iterator.remove();
                    socketChannel = (SocketChannel) key.channel();
                    //套接字通道设置为非阻塞模式
                    socketChannel.configureBlocking(false);

                    //连接就绪事件
                    if(key.isConnectable()){
                        socketChannel = (SocketChannel) key.channel();
                        //判断连接是否完成
                        int i =0;
                        while(! socketChannel.finishConnect()){
                            if(++i>10){
                                throw  new RuntimeException("socket连接超时");
                            }
                            System.out.println("sock连接未完成,等待中....");
                            try {
                                Thread.sleep(1000);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                        //向socket通道 注册读就绪事件
                        socketChannel.register(selector, SelectionKey.OP_READ);
                    }else if(key.isReadable()){
                        //SocketChannel socketChannel = (SocketChannel) key.channel();
                        ByteBuffer byteBuffer = ByteBuffer.allocate(100);
                        int len = socketChannel.read(byteBuffer);
                        /*StringBuffer  dataBuffer= new StringBuffer();
                        while( -1 != len){
                            //将写模式变为读模式
                            byteBuffer.flip();
                            CharBuffer charBuffer = byteBuffer.asCharBuffer();
                            dataBuffer.append(charBuffer.array());
                            byteBuffer.clear();
                            len = socketChannel.read(byteBuffer);
                        }*/
                        byteBuffer.flip();
                        //读取完毕
                        if(byteBuffer.limit()>0){
                            System.out.println("来自服务端消息:" + new String(byteBuffer.array()).trim());
                        }
                    }else if(key.isWritable()){
                        //暂时还没想明白这个写就绪事件干嘛用的。。。
                        System.out.println("暂不处理");
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {

        //打开一个SocketChannel实例 并设置为false
        SocketChannel socketChannel = SocketChannel.open();
        socketChannel.configureBlocking(false);
        //绑定ip +端口
        socketChannel.connect(new InetSocketAddress("127.0.0.1",1024));
        //打开一个选择器
        Selector selector = Selector.open();
        //向 serverSocketChannel 注册 连接就绪事件
        socketChannel.register(selector, SelectionKey.OP_CONNECT);
        //开启线程进行监听
        NioClientListener listener = new NioClientListener (selector);
        listener.start();
        //进行控制太输入 写事件 进行通讯
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            //java IO 阻塞读取数据
            String data = bufferedReader.readLine();
            if("exit".equals(data)){
                socketChannel.close();
                System.out.println("主线程关闭.....");
                System.exit(0);
            }
            ByteBuffer buffer = ByteBuffer.wrap(data.getBytes());
            socketChannel.write(buffer);
        }
    }
}

来源： http://www.open-open.com/code/view/1453981022933