JDK1.7 AIO

工程结构图:


Helper.java文件内容如下:

package com.shihuan.aio.util;

import java.util.Random;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;

public class Helper {

	private static BlockingQueue<String> words;
    private static Random random;
     
    public Helper() throws InterruptedException{
        words = new ArrayBlockingQueue<String>(5);
        words.put("hi");
        words.put("who");
        words.put("what");
        words.put("where");
        words.put("bye");  
         
        random = new Random();
    }
     
    public String getWord(){
        return words.poll();
    }
 
    public void sleep() {
        try {
            TimeUnit.SECONDS.sleep(random.nextInt(3));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }  
     
    public static void sleep(long l) {
        try {
            TimeUnit.SECONDS.sleep(l);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
     
    public static String getAnswer(String question){
        String answer = null;
         
        switch(question){
        case "who":
            answer = "我是小娜\n";
            break;
        case "what":
            answer = "我是来帮你解闷的\n";
            break;
        case "where":
            answer = "我来自外太空\n";
            break;
        case "hi":
            answer = "hello\n";
            break;
        case "bye":
            answer = "88\n";
            break;
        default:
                answer = "请输入 who， 或者what， 或者where";
        }
         
        return answer;
    }
	
}

CharsetHelper.java文件内容如下:

package com.shihuan.aio.util;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;

public class CharsetHelper {

	private static final String UTF_8 = "UTF-8";
    private static CharsetEncoder encoder = Charset.forName(UTF_8).newEncoder();
    private static CharsetDecoder decoder = Charset.forName(UTF_8).newDecoder();
     
    public static ByteBuffer encode(CharBuffer in) throws CharacterCodingException {
        return encoder.encode(in);
    }
 
    public static CharBuffer decode(ByteBuffer in) throws CharacterCodingException {
        return decoder.decode(in);
    }
	
}

SocketServer.java文件内容如下:

package com.shihuan.aio.server;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.StandardSocketOptions;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.AsynchronousChannelGroup;
import java.nio.channels.AsynchronousServerSocketChannel;
import java.nio.channels.AsynchronousSocketChannel;
import java.nio.channels.CompletionHandler;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.Executors;

import com.shihuan.aio.util.Helper;

public class SocketServer {

	private final AsynchronousServerSocketChannel server;
	//写队列，因为当前一个异步写调用还没完成之前，调用异步写会抛WritePendingException
    //所以需要一个写队列来缓存要写入的数据，这是AIO比较坑的地方
    private final Queue<ByteBuffer> queue = new LinkedList<ByteBuffer>();
    private boolean writing = false;
	
	public SocketServer() throws IOException {
		//设置线程数为CPU核数
        AsynchronousChannelGroup channelGroup = AsynchronousChannelGroup.withFixedThreadPool(Runtime.getRuntime().availableProcessors(), Executors.defaultThreadFactory());
        server = AsynchronousServerSocketChannel.open(channelGroup);
        //重用端口
        server.setOption(StandardSocketOptions.SO_REUSEADDR, true);
        //绑定端口并设置连接请求队列长度
        server.bind(new InetSocketAddress(8383), 80);
	}

	public void listen() {
        System.out.println(Thread.currentThread().getName() + ": run in listen method" );
        //开始接受第一个连接请求
        server.accept(null, new CompletionHandler<AsynchronousSocketChannel, Object>(){                       
            @Override
            public void completed(AsynchronousSocketChannel channel, Object attachment) {
                System.out.println(Thread.currentThread().getName() + ": run in accept completed method" );
                 
                //先安排处理下一个连接请求，异步非阻塞调用，所以不用担心挂住了
                //这里传入this是个地雷，小心多线程
                server.accept(null, this);
                //处理连接读写
                handle(channel);
            }
 
            private void handle(final AsynchronousSocketChannel channel) {
                System.out.println(Thread.currentThread().getName() + ": run in handle method" );
                //每个AsynchronousSocketChannel，分配一个缓冲区
                final ByteBuffer readBuffer = ByteBuffer.allocateDirect(1024);
                readBuffer.clear();
                channel.read(readBuffer, null, new CompletionHandler<Integer, Object>(){
 
                    @Override
                    public void completed(Integer count, Object attachment) {
                        System.out.println(Thread.currentThread().getName() + ": run in read completed method" );  
                         
                        if(count > 0){
                            try{
                                readBuffer.flip();
                                //CharBuffer charBuffer = CharsetHelper.decode(readBuffer); 
                                CharBuffer charBuffer = Charset.forName("UTF-8").newDecoder().decode(readBuffer);
                                String question = charBuffer.toString(); 
                                String answer = Helper.getAnswer(question);
                                /*//写入也是异步调用，也可以使用传入CompletionHandler对象的方式来处理写入结果
                                //channel.write(CharsetHelper.encode(CharBuffer.wrap(answer)));                            
                                try{
                                    channel.write(Charset.forName("UTF-8").newEncoder().encode(CharBuffer.wrap(answer)));
                                }
                                //Unchecked exception thrown when an attempt is made to write to an asynchronous socket channel and a previous write has not completed.
                                //看来操作系统也不可靠
                                catch(WritePendingException wpe){
                                    //休息一秒再重试，如果失败就不管了
                                    Helper.sleep(1);
                                    channel.write(Charset.forName("UTF-8").newEncoder().encode(CharBuffer.wrap(answer)));
                                }*/
                                writeStringMessage(channel, answer);
                                 
                                readBuffer.clear();
                            }
                            catch(IOException e){
                                e.printStackTrace();
                            }
                        }
                        else{
                            try {
                                //如果客户端关闭socket，那么服务器也需要关闭，否则浪费CPU
                                channel.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                         
                        //异步调用OS处理下个读取请求
                        //这里传入this是个地雷，小心多线程
                        channel.read(readBuffer, null, this);
                    }
 
                    /**
                     * 服务器读失败处理
                     * @param exc
                     * @param attachment
                     */
                    @Override
                    public void failed(Throwable exc, Object attachment) {
                        System.out.println("server read failed: " + exc);         
                        if(channel != null){
                            try {
                                channel.close();
                            } catch (IOException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                     
                });                            
            }
 
            /**
             * 服务器接受连接失败处理
             * @param exc
             * @param attachment
             */
            @Override
            public void failed(Throwable exc, Object attachment) {
                System.out.println("server accept failed: " + exc);
            }
             
        });
    }
     
    /**
     * Enqueues a write of the buffer to the channel.
     * The call is asynchronous so the buffer is not safe to modify after
     * passing the buffer here.
     *
     * @param buffer the buffer to send to the channel
     */
    private void writeMessage(final AsynchronousSocketChannel channel, final ByteBuffer buffer) {
        boolean threadShouldWrite = false;
 
        synchronized(queue) {
            queue.add(buffer);
            // Currently no thread writing, make this thread dispatch a write
            if (!writing) {
                writing = true;
                threadShouldWrite = true;
            }
        }
 
        if (threadShouldWrite) {
            writeFromQueue(channel);
        }
    }
 
    private void writeFromQueue(final AsynchronousSocketChannel channel) {
        ByteBuffer buffer;
 
        synchronized (queue) {
            buffer = queue.poll();
            if (buffer == null) {
                writing = false;
            }
        }
 
        // No new data in buffer to write
        if (writing) {
            writeBuffer(channel, buffer);
        }
    }
 
    private void writeBuffer(final AsynchronousSocketChannel channel, ByteBuffer buffer) {
        channel.write(buffer, buffer, new CompletionHandler<Integer, ByteBuffer>() {
            @Override
            public void completed(Integer result, ByteBuffer buffer) {
                if (buffer.hasRemaining()) {
                    channel.write(buffer, buffer, this);
                } else {
                    // Go back and check if there is new data to write
                    writeFromQueue(channel);
                }
            }
 
            @Override
            public void failed(Throwable exc, ByteBuffer attachment) {
                System.out.println("server write failed: " + exc);
            }
        });
    }
    
    /**
     * Sends a message
     * @param string the message
     * @throws CharacterCodingException 
     */
    private void writeStringMessage(final AsynchronousSocketChannel channel, String msg) throws CharacterCodingException {
        writeMessage(channel, Charset.forName("UTF-8").newEncoder().encode(CharBuffer.wrap(msg)));
    }

	public static void main(String[] args) throws IOException {
		SocketServer socketServer = new SocketServer();
		socketServer.listen();
	}

}

SocketClient.java文件内容如下:

package com.shihuan.aio.client;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.StandardSocketOptions;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.AsynchronousChannelGroup;
import java.nio.channels.AsynchronousSocketChannel;
import java.nio.channels.CompletionHandler;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;

import com.shihuan.aio.util.CharsetHelper;
import com.shihuan.aio.util.Helper;

public class SocketClient implements Runnable {

	private AsynchronousSocketChannel channel;
    private Helper helper;
    private CountDownLatch latch;
    private final Queue<ByteBuffer> queue = new LinkedList<ByteBuffer>();
    private boolean writing = false;
	
	public SocketClient(AsynchronousChannelGroup channelGroup, CountDownLatch latch) throws IOException, InterruptedException {
		this.latch = latch;
        helper = new Helper();
        initChannel(channelGroup);
	}
	
	private void initChannel(AsynchronousChannelGroup channelGroup) throws IOException {
        //在默认channel group下创建一个socket channel
        channel = AsynchronousSocketChannel.open(channelGroup);
        //设置Socket选项
        channel.setOption(StandardSocketOptions.TCP_NODELAY, true);
        channel.setOption(StandardSocketOptions.SO_KEEPALIVE, true);
        channel.setOption(StandardSocketOptions.SO_REUSEADDR, true);
    }
	
	private void shutdown() throws IOException {
        if(channel != null){
            channel.close();
        }
         
        latch.countDown();                         
    }
     
    /**
     * Enqueues a write of the buffer to the channel.
     * The call is asynchronous so the buffer is not safe to modify after
     * passing the buffer here.
     *
     * @param buffer the buffer to send to the channel
     */
    private void writeMessage(final ByteBuffer buffer) {
        boolean threadShouldWrite = false;
 
        synchronized(queue) {
            queue.add(buffer);
            // Currently no thread writing, make this thread dispatch a write
            if (!writing) {
                writing = true;
                threadShouldWrite = true;
            }
        }
 
        if (threadShouldWrite) {
            writeFromQueue();
        }
    }
 
    private void writeFromQueue() {
        ByteBuffer buffer;
 
        synchronized (queue) {
            buffer = queue.poll();
            if (buffer == null) {
                writing = false;
            }
        }
 
        // No new data in buffer to write
        if (writing) {
            writeBuffer(buffer);
        }
    }
 
    private void writeBuffer(ByteBuffer buffer) {
        channel.write(buffer, buffer, new CompletionHandler<Integer, ByteBuffer>() {
            @Override
            public void completed(Integer result, ByteBuffer buffer) {
                if (buffer.hasRemaining()) {
                    channel.write(buffer, buffer, this);
                } else {
                    // Go back and check if there is new data to write
                    writeFromQueue();
                }
            }
 
            @Override
            public void failed(Throwable exc, ByteBuffer attachment) {
            }
        });
    }
 
    /**
     * Sends a message
     * @param string the message
     * @throws CharacterCodingException 
     */
    public void writeStringMessage(String msg) throws CharacterCodingException {
        writeMessage(Charset.forName("UTF-8").newEncoder().encode(CharBuffer.wrap(msg)));
    }

	@Override
	public void run() {
		System.out.println(Thread.currentThread().getName() + "---run");
        
        //连接服务器
        channel.connect(new InetSocketAddress("localhost", 8383), null, new CompletionHandler<Void, Void>(){
            final ByteBuffer readBuffer = ByteBuffer.allocateDirect(1024);
             
            @Override
            public void completed(Void result, Void attachment) {
                //连接成功后, 异步调用OS向服务器写一条消息
                try {
                    //channel.write(CharsetHelper.encode(CharBuffer.wrap(helper.getWord())));
                    writeStringMessage(helper.getWord());
                } catch (CharacterCodingException e) {
                    e.printStackTrace();
                }
                 
                //helper.sleep();//等待写异步调用完成
                readBuffer.clear();
                //异步调用OS读取服务器发送的消息
                channel.read(readBuffer, null, new CompletionHandler<Integer, Object>(){
 
                    @Override
                    public void completed(Integer result, Object attachment) {
                        try{
                            //异步读取完成后处理
                            if(result > 0){
                                readBuffer.flip();
                                CharBuffer charBuffer = CharsetHelper.decode(readBuffer);
                                String answer = charBuffer.toString(); 
                                System.out.println(Thread.currentThread().getName() + "---" + answer);
                                readBuffer.clear();
                                 
                                String word = helper.getWord();
                                if(word != null){
                                    //异步写
                                    //channel.write(CharsetHelper.encode(CharBuffer.wrap(word)));
                                    writeStringMessage(word);
                                    //helper.sleep();//等待异步操作
                                    channel.read(readBuffer, null, this);
                                }
                                else{
                                    //不想发消息了，主动关闭channel
                                    shutdown();
                                }
                            }
                            else{
                                //对方已经关闭channel，自己被动关闭，避免空循环
                                shutdown();
                            }                                                      
                        }
                        catch(Exception e){
                            e.printStackTrace();
                        }                      
                    }                  
 
                    /**
                     * 读取失败处理
                     * @param exc
                     * @param attachment
                     */
                    @Override
                    public void failed(Throwable exc, Object attachment) {
                        System.out.println("client read failed: " + exc);
                        try {
                            shutdown();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                     
                });
            }
 
            /**
             * 连接失败处理
             * @param exc
             * @param attachment
             */
            @Override
            public void failed(Throwable exc, Void attachment) {
                System.out.println("client connect to server failed: " + exc);
                 
                try {
                    shutdown();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }          
        });
	}
	
	public static void main(String[] args) throws IOException, InterruptedException {
		int sleepTime = Integer.parseInt(args[0]);
        Helper.sleep(sleepTime);
         
        AsynchronousChannelGroup channelGroup = AsynchronousChannelGroup.withFixedThreadPool(Runtime.getRuntime().availableProcessors(), Executors.defaultThreadFactory());
        //只能跑一个线程，第二个线程connect会挂住，暂时不明原因
        final int THREAD_NUM = 1;
        CountDownLatch latch = new CountDownLatch(THREAD_NUM);
         
        //创建个多线程模拟多个客户端，模拟失败，无效
        //只能通过命令行同时运行多个进程来模拟多个客户端
        for(int i=0; i<THREAD_NUM; i++){
        	SocketClient c = new SocketClient(channelGroup, latch);
            Thread t = new Thread(c);
            System.out.println(t.getName() + "---start");
            t.start();
            //让主线程等待子线程处理再退出, 这对于异步调用无效
            //t.join();
        }          
         
        latch.await();
         
        if(channelGroup !=null){
            channelGroup.shutdown();
        }
	}

}

运行步骤:
1、先在eclipse里运行SocketServer.java文件。
2、打开cmd窗口进入E:\BaiduYunDownload\workspaces\javaaio\bin目录。
3、E:\BaiduYunDownload\workspaces\javaaio\bin>java -classpath .\ com.shihuan.aio.client.SocketClient 1


eclipse中的server端控制台截图如下: