传统的-阻塞式代码

public class BioSocketServer {public static void main(String[] args) throws IOException {//建立socket连接，并监听端口ServerSocket serverSocket = new ServerSocket(8888);while (true) {//这里阻塞等待连接Socket client = serverSocket.accept();//当有连接建立时线程处理 只是演示 真实环境所有线程都应该通过线程池创建new Thread(new Runnable() {@Overridepublic void run() {try {//处理器handler(client);} catch (IOException e) {e.printStackTrace();}}}).start();}
}
/**
* 处理器
*/
private static void handler(Socket client) throws IOException {byte[] bytes = new byte[1024];// 第二个阻塞，获取客户端发来的数据，假如客户端没有发数据，则会一直阻塞int read = clientSocket.getInputStream().read(bytes);if (read != -1) {System.out.println( new String(bytes, 0, read));}}
}

基础的reactor模型-单reactor单线程处理 代码

public class NioSelectorSignThreadServer {public static void main(String[] args) throws IOException {// 创建Nio连接通道ServerSocketChannel serverSocket = ServerSocketChannel.open();//绑定监听端口serverSocket.socket().bind(new InetSocketAddress(8888));// 设置ServerSocketChannel为非阻塞serverSocket.configureBlocking(false);// 打开Selector处理Channel，即创建epoll 这里底层调用了系统的epoll_create方法，创建了epoll对象Selector selector = Selector.open();// 把ServerSocketChannel注册到selector上，且绑定OP_ACCEPT事件 这里底层调用了epoll_ctl将事件加入到epoll中serverSocket.register(selector, SelectionKey.OP_ACCEPT);//标注1System.out.println("nio服务启动成功");while (true) {// 这里是阻塞的 nio并非是异步非阻塞 而是同步阻塞// 阻塞等待需要处理的事件发生 这里调用了系统的epoll_wait方法,轮训就绪队列rdlist// 返回的select是此次获取的已就绪事件个数int select = selector.select();if(select <= 0){continue;}// 获取selector中注册的全部事件的就绪事件 SelectionKey 实例Set<SelectionKey> selectionKeys = selector.selectedKeys();Iterator<SelectionKey> iterator = selectionKeys.iterator();// 遍历SelectionKey对事件进行处理while (iterator.hasNext()) {SelectionKey selectionKey = iterator.next();// OP_ACCEPT事件(相对于server端，accept事件就是客户端注册事件，在客户端就是OP_CONNECT事件)// 开始进行连接处理，和读事件注册if (selectionKey.isAcceptable()) {// 注意这里的channel类型，因为OP_ACCEPT事件是ServerSocketChannel注册的(标注1)，所以OP_ACCEPT事件返回的对象也是ServerSocketChannelServerSocketChannel server = (ServerSocketChannel)selectionKey.channel();SocketChannel socketChannel = server.accept();// 这里要注意将客户端连接注册成了异步，select模式属于异步，必须要注册成异步才支持select模式socketChannel.configureBlocking(false);// 注册需要的事件 读(OP_READ)事件socketChannel.register(selector,SelectionKey.OP_READ|SelectionKey.OP_WRITE);System.out.println("客户端连接成功");// 读事件，处理客户端传过来的数据} else if (selectionKey.isReadable()) {SocketChannel socketChannel = (SocketChannel)selectionKey.channel();ByteBuffer byteBuffer = ByteBuffer.allocateDirect(1024);int len = socketChannel.read(byteBuffer);// 如果有数据，把数据打印出来if (len > 0) {System.out.println("接收到消息：" + newString(byteBuffer.array()));selectionKey.interestOps(SelectionKey.OP_READ);// 如果客户端断开连接，关闭Socket} else if (len == -1) {System.out.println("客户端断开连接");socketChannel.close();}//写事件 水平触发 需要移除该事件 需要时再注册} else if(selectionKey.isWritable()){SocketChannel socketChannel = (SocketChannel)selectionKey.channel();System.out.println("write事件");// NIO事件触发是水平触发selectionKey.interestOps(SelectionKey.OP_READ);}//将已处理的事件移除，防止二次处理iterator.remove();}}}
} 

多线程处理-单reactor-多线程处理

将上面的处理 select 事件部分改为多线程即可

public class NettyServer {public static void main(String[] args) throws InterruptedException {NioEventLoopGroup parentGroup = new NioEventLoopGroup();NioEventLoopGroup childGroup = new NioEventLoopGroup();try{ServerBootstrap bootstrap = new ServerBootstrap();bootstrap.group(parentGroup,childGroup).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel ch) throwsException {ChannelPipeline pipeline = ch.pipeline();
// pipeline.addLast(new FixedLengthFrameDecoder(6));pipeline.addLast(newDelimiterBasedFrameDecoder(10240, Unpooled.copiedBuffer("####".getBytes())));pipeline.addLast(newStringDecoder(CharsetUtil.UTF_8));pipeline.addLast(new ServerHandler3());
// pipeline.addLast(new ChatSocketSer)}});ChannelFuture future = bootstrap.bind(8888).sync();System.out.println("启动成功");future.channel().closeFuture().sync();}finally {parentGroup.shutdownGracefully();childGroup.shutdownGracefully();}}
}