Netty 代码-Socket 案例

socket 编程

同样功能的不同实现方式

1. 阻塞I/O

public class PlainOioServer {

    public void serve(int port) throws IOException {
        final ServerSocket socket = new ServerSocket(port);     //1
        try {
            for (;;) {
                final Socket clientSocket = socket.accept();    //2
                System.out.println("Accepted connection from " + clientSocket);

                new Thread(new Runnable() {                     //3
                    @Override
                    public void run() {
                        OutputStream out;
                        try {
                            out = clientSocket.getOutputStream();
                            out.write("Hi!\r\n".getBytes(Charset.forName("UTF-8")));                                      //4
                            out.flush();
                            clientSocket.close();               //5

                        } catch (IOException e) {
                            e.printStackTrace();
                            try {
                                clientSocket.close();
                            } catch (IOException ex) {
                                // ignore on close
                            }
                        }
                    }
                }).start();                                     //6
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2. 非阻塞IO

public class PlainNioServer {
    public void serve(int port) throws IOException {
        ServerSocketChannel serverChannel = ServerSocketChannel.open();
        serverChannel.configureBlocking(false);
        ServerSocket ss = serverChannel.socket();
        InetSocketAddress address = new InetSocketAddress(port);
        ss.bind(address);                                           //1
        Selector selector = Selector.open();                        //2
        serverChannel.register(selector, SelectionKey.OP_ACCEPT);   //3
        final ByteBuffer msg = ByteBuffer.wrap("Hi!\r\n".getBytes());
        for (;;) {
            try {
                selector.select();                                  //4
            } catch (IOException ex) {
                ex.printStackTrace();
                // handle exception
                break;
            }
            Set<SelectionKey> readyKeys = selector.selectedKeys();  //5
            Iterator<SelectionKey> iterator = readyKeys.iterator();
            while (iterator.hasNext()) {
                SelectionKey key = iterator.next();
                iterator.remove();
                try {
                    if (key.isAcceptable()) {                       //6
                        ServerSocketChannel server = (ServerSocketChannel)key.channel();
                        SocketChannel client = server.accept();
                        client.configureBlocking(false);
                        client.register(selector, 
                            SelectionKey.OP_WRITE | SelectionKey.OP_READ, 
                            msg.duplicate());                       //7
                        System.out.println("Accepted connection from " + client);
                    }
                    if (key.isWritable()) {                         //8
                        SocketChannel client = (SocketChannel)key.channel();
                        ByteBuffer buffer = (ByteBuffer)key.attachment();
                        while (buffer.hasRemaining()) {
                            if (client.write(buffer) == 0) {        //9
                                break;
                            }
                        }
                        client.close();                             //10
                    }
                } catch (IOException ex) {
                    key.cancel();
                    try {
                        key.channel().close();
                    } catch (IOException cex) {
                        // ignore on close
                    }
                }
            }
        }
    }
}

3. Netty

public class NettyOioServer {

    public void server(int port) throws Exception {
        final ByteBuf buf = Unpooled.unreleasableBuffer(
                Unpooled.copiedBuffer("Hi!\r\n", Charset.forName("UTF-8")));
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();                          //1

            b.group(group)                                                      //2
             .channel(NioServerSocketChannel.class)
             .localAddress(new InetSocketAddress(port))
             .childHandler(new ChannelInitializer<SocketChannel>() {            //3
                 @Override
                 public void initChannel(SocketChannel ch) 
                     throws Exception {
                     ch.pipeline().addLast(new ChannelInboundHandlerAdapter() { //4
                         @Override
                         public void channelActive(ChannelHandlerContext ctx) throws Exception {
                             ctx.writeAndFlush(buf.duplicate()).addListener(ChannelFutureListener.CLOSE);//5
                         }
                     });
                 }
             });
            ChannelFuture f = b.bind().sync();                                  //6
            f.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully().sync();                                  //7
        }
    }
}