基于NIO-主从Reactor多线程模型的实现

具体实现原理和模型图，请参考：Reactor模型介绍

单Reactor单线程实现，请参考：基于NIO-Reactor的介绍和单Reactor单线程模型的实现

单Reactor多线程模型实现，请参考：基于NIO-单Reactor多线程模型的实现　　

 

在单Reactor多线程模型，只有一个selector，selector负责accpet，read，write事件的维护。

而主从Reactor多线程模型，将使用两个selector，一个主selector专门维护accept事件，当接收到accept事件，将该连接交给从selector，从selector维护该连接的read和write事件。

主从selector的方式，将连接和数据处理完全分开维护，将大大提高并发量。

主从Reactor的实现：

/**
 * 主从Reactor多线程模型
 */
public class MainAndSubReactorMultiThreadMode {

    public static void main(String[] args) {
        /**
         * 初始化一个线程池，然后创建一个主Reactor，并加入一个从Reactor.
         */
        ThreadPool.getPool().init(3);
        new MainReactor(8089).addSub(new SubReactor()).run();

    }

}

/**
 * 主Reactor
 */
class MainReactor{


    /**
     * 维护一个从Reactor
     */
    private SubReactor subReactor;

    private int port;


    private Selector selector;

    private ServerSocketChannel servChannel;

    private volatile boolean stop;

    public MainReactor(int port) {
        try {
            selector = Selector.open();
            servChannel = ServerSocketChannel.open();
            servChannel.configureBlocking(false);
            servChannel.socket().bind(new InetSocketAddress(port), 1024);
            SelectionKey sk = servChannel.register(selector, SelectionKey.OP_ACCEPT);
            stop=false;
            this.port=port;
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }
    }
/**
     * 添加子Reactor
     * @param subReactor
     * @return
     */
    public MainReactor addSub(SubReactor subReactor){
        this.subReactor=subReactor;
        this.subReactor.run();
        return this;
    }

    public void run() {
        System.out.println("主reactor开始启动了,监听端口："+port+".......");
        while (!stop) {
            try {
                selector.select(1000);
                Set<SelectionKey> selectedKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectedKeys.iterator();
                SelectionKey key = null;
                while (it.hasNext()) {
                    key = it.next();
                    it.remove();
                    try {
                        disptach(key);
                    } catch (Exception e) {
                        if (key != null) {
                            key.cancel();
                            if (key.channel() != null)
                                key.channel().close();
                        }
                    }
                }
            } catch (Throwable t) {
                t.printStackTrace();
            }
        }
    }
private void disptach(SelectionKey key) {
        if(key.isValid()){
            /**
             * 主Reactor只关心Accept事件
             */
            if(key.isAcceptable()){
                new MultiAcceptor(key).addSub(this.subReactor).run();
            }

            //如果未使用了从Reactor
            if(this.subReactor==null){
                if (key.isReadable()){
                new MultiReadHandler(key).run();
            }
            if(key.isWritable()){
                new MultiWriteHandler(key).run();
            }
            }

        }
    }
}

　　

/**
 * 从Reactor
 */
class SubReactor {

    private Selector selector;

    private volatile boolean stop;

    public SubReactor() {
        try {
            selector = SelectorProvider.provider().openSelector();
            stop=false;
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(1);
        }
    }

    /**
     * 将主Reactor中的Channel注册到从Reactor中的selector
     * @param sc
     */
    public void register(SocketChannel sc){
        try {
            sc.register(selector,SelectionKey.OP_READ|SelectionKey.OP_WRITE);
        } catch (ClosedChannelException e) {
            e.printStackTrace();
        }
    }
public void run() {
        ThreadPool.getPool().submit(new Runnable() {
            @Override
            public void run() {
                System.out.println("从reactor开始启动了。。。。。");
                while (!stop) {
                    try {
                        selector.select(1000);
                        Set<SelectionKey> selectedKeys = selector.selectedKeys();
                        Iterator<SelectionKey> it = selectedKeys.iterator();
                        SelectionKey key = null;
                        while (it.hasNext()) {
                            key = it.next();
                            it.remove();
                            try {
                                disptach(key);
                            } catch (Exception e) {
                                if (key != null) {
                                    key.cancel();
                                    if (key.channel() != null)
                                        key.channel().close();
                                }
                            }
                        }
                    } catch (Throwable t) {
                        t.printStackTrace();
                    }
                }
            }
        });

    }
private void disptach(SelectionKey key) {
        /**
         * 从Reactor只关心读和写事件
         */
        if(key.isValid()){

            if (key.isReadable()){
                new MultiReadHandler(key).run();
            }

            if(key.isWritable()){
                new MultiWriteHandler(key).run();
            }
        }
    }
}

class MultiAcceptor  {

    private SubReactor subReactor;

    private SelectionKey selectionKey;

    public MultiAcceptor(SelectionKey selectionKey) {
        this.selectionKey = selectionKey;
    }

    public MultiAcceptor addSub(SubReactor subReactor){
        this.subReactor=subReactor;
        return this;
    }
public void run() {
        try {
            ServerSocketChannel ssc = (ServerSocketChannel) selectionKey.channel();
            SocketChannel sc = ssc.accept();
            sc.configureBlocking(false);
            if(subReactor==null){
                Selector selector = selectionKey.selector();
                SelectionKey sk = sc.register(selector, SelectionKey.OP_READ);
            }else {
                System.out.println("accept");
                subReactor.register(sc);
            }

        }catch (Exception e){
            e.printStackTrace();
        }

    }
}

class MultiReadHandler {

    private SelectionKey selectionKey;

    public MultiReadHandler(SelectionKey selectionKey) {
        this.selectionKey = selectionKey;
    }



    public void run() {
        try {
            final SocketChannel sc = (SocketChannel) selectionKey.channel();
            //使用线程池，异步处理读请求
            ThreadPool.getPool().submit(new Runnable() {
                @Override
                public void run() {
                    doRead(sc);
                }
            });

            //处理完读请求，将通道注册为写
            Selector selector = selectionKey.selector();
            SelectionKey sk = sc.register(selector, SelectionKey.OP_WRITE);
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    private void doRead(SocketChannel ssc) {
        System.out.println("读取数据，然后做一些数据处理");
    }
}

class MultiWriteHandler {

    private SelectionKey selectionKey;

    public MultiWriteHandler(SelectionKey selectionKey) {
        this.selectionKey = selectionKey;
    }



    private void doWrite(SocketChannel sc) {
        System.out.println("处理写。。。");
    }

    public void run() {
        try {
            final SocketChannel sc = (SocketChannel) selectionKey.channel();
            //使用线程池，异步处理写请求
            ThreadPool.getPool().submit(new Runnable() {
                @Override
                public void run() {
                    doWrite(sc);
                }
            });
            //写完后，将通道注册为读
            Selector selector = selectionKey.selector();
            SelectionKey sk = sc.register(selector, SelectionKey.OP_READ);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

/**
 * 示例-线程池
 */
class ThreadPool{

    public static final ThreadPool pool = new ThreadPool();

    private boolean init=false;

    private  static ExecutorService executorService;

    private ThreadPool(){};

    public synchronized void init(int size){
        if(!init){
            executorService=Executors.newFixedThreadPool(size);
            init=true;
        }else {
            System.out.println("the thread pool had inited");
        }

    }

    public static ThreadPool getPool(){
       return pool;
    }

    public  void submit(Runnable runnable){
        if(init){
            executorService.submit(runnable);
        }else {
            throw new RuntimeException("the thread pool is not inited");
        }
    }
}