Reactor示例

Reactor模型相關內容可參考：https://blog.csdn.net/skh2015java/article/details/106721630

Reactor模型示例
mainSelector 負責處理ACCEPT I/O事件，處理ACCEPT的業務邏輯Handler交給executorService線程池處理
subSelector負責處理READ I/O事件，處理READ和邏輯的Handler交給executorService線程處理

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;



public class ReactorTask {


    public static void main(String[] args) throws IOException {
        new ReactorTask().startReactor();
    }



    final int  PORT = 7786;
    final Selector  mainSelector;
    final Selector subSelector;
    final ServerSocketChannel serverSocketChannel;

    final Thread  subThread ;
    final ExecutorService executorService = Executors.newFixedThreadPool(8);

    private ConcurrentLinkedQueue <SocketChannel> socketChannels = new ConcurrentLinkedQueue<>();

    public ReactorTask() throws IOException {
        mainSelector = Selector.open();
        subSelector = Selector.open();

        subThread = new Thread(new SubThreadTask());

        serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.configureBlocking(false);
        serverSocketChannel.bind(new InetSocketAddress(PORT));

        serverSocketChannel.register(mainSelector, SelectionKey.OP_ACCEPT);
    }

    public void startReactor(){
        try{
            subThread.start();
            while (!Thread.interrupted()){
                mainSelector.select();  //阻塞等待ACCEPT事件
                Iterator<SelectionKey> it = mainSelector.selectedKeys().iterator();
                while (it.hasNext()) {
                    SelectionKey key=  it.next();
                    if (key.isAcceptable()) {
                        ServerSocketChannel server = (ServerSocketChannel)key.channel();
                        SocketChannel sc = server.accept();
                        executorService.execute(new ServerSocketChannelAcceptHandle(sc));
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }



    class SubThreadTask implements Runnable {
        @Override
        public void run() {
            while (!Thread.currentThread().isInterrupted()) {
                try {
                       subSelector.select();
                        while (!socketChannels.isEmpty()){
                            SocketChannel socketChannel  = socketChannels.poll();
                            socketChannel.configureBlocking(false);
                            socketChannel.register(subSelector,SelectionKey.OP_READ);
                            ByteBuffer buffer = ByteBuffer.wrap("register success".getBytes());
                            socketChannel.write(buffer);
                        }


                    Iterator<SelectionKey> selectedKeys = subSelector.selectedKeys().iterator();
                    while (selectedKeys.hasNext()){
                        SelectionKey key =  selectedKeys.next();
                        if (!key.isValid()) {
                            break;
                        }
                        if (key.isReadable()){
                            executorService.execute(new SocketChannelReadHandle(key));
                        }
                    }
                } catch (Exception e) {
                    System.out.println("catch Exception "+ e);
                }
            }
        }
    }


    class SocketChannelReadHandle implements Runnable {

        private SelectionKey key;
        ByteBuffer buffer = ByteBuffer.allocate(128);

        public SocketChannelReadHandle(SelectionKey key){
            this.key = key;
        }

        @Override
        public void run() {
            try {
                if (!key.isValid()){
                    return;
                }
                SocketChannel channel = (SocketChannel)key.channel();
                buffer.clear();
                if ( channel.read(buffer) > 0 ){
                    buffer.flip();
                    System.out.println("handle Thread:"+Thread.currentThread().getName() +"  subReactor  read:"+Charset.forName("UTF-8").decode(buffer).toString() );
                    buffer.clear();
                    buffer.put("I am subReactor".getBytes());
                    buffer.flip();
                    channel.write(buffer);
                }
            } catch (Exception e) {
                System.out.println(" caught "+ e + " closing channel");
                try {
                        key.channel().close();
                } catch (Exception e1) {
                    System.out.println("caught" + e1 + "channel has closed ");
                }
            }
        }
    }


    class ServerSocketChannelAcceptHandle implements Runnable {
        private SocketChannel channel;

        public ServerSocketChannelAcceptHandle(SocketChannel channel){
            this.channel = channel;
        }


        @Override
        public void run() {
            try {
                socketChannels.offer(channel);
                subSelector.wakeup();
                System.out.println("handle Thread:"+Thread.currentThread().getName() + " mainReactor accept remoteAddr:"+ channel.getRemoteAddress().toString()+" and register over!");
            } catch (ClosedChannelException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}