基于jdk的网络编程和使用Netty的比较

一,jdk

1,使用OIO的阻塞版本:

public class JDKOioServer {    public void server(int port) throws IOException {        final ServerSocket serverSocket = new ServerSocket(port);        try{            for(;;){                final Socket csocket = serverSocket.accept();                System.out.println("Accepted connection from"+csocket);                new Thread(new Runnable() {                      @Override                    public void run() {                        OutputStream out;                        try{                            out = csocket.getOutputStream();                            out.write("Hi!\r\n".getBytes(Charset.forName("UTF-8")));                            out.flush();                            csocket.close();                        }catch (IOException e){                            e.printStackTrace();                            }finally {                            try {                                csocket.close();                            }catch (IOException ex){                                                            }                        }                    }                }).start();            }          }catch (IOException e){            e.printStackTrace();        }            }}

2,使用NIO的非阻塞版本:

public class JDKNioServer {    public void server(int port)throws IOException{        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();        serverSocketChannel.configureBlocking(false);        ServerSocket socket = serverSocketChannel.socket();        InetSocketAddress address = new InetSocketAddress(port);        socket.bind(address);        Selector selector = Selector.open();        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);        final ByteBuffer msg = ByteBuffer.wrap("Hi\r\n".getBytes());        for(;;){            try{                selector.select();            }catch (IOException e){                e.printStackTrace();                break;            }            Set<SelectionKey> readyKeys = selector.selectedKeys();            Iterator<SelectionKey> iterator = readyKeys.iterator();            while(iterator.hasNext()){                SelectionKey key = iterator.next();                iterator.remove();                try{                    if(key.isAcceptable()){                        ServerSocketChannel server = (ServerSocketChannel) key.channel();                        SocketChannel client = server.accept();                        client.configureBlocking(false);                        client.register(selector,SelectionKey.OP_WRITE|SelectionKey.OP_READ,msg.duplicate());                        System.out.println("Accepted connection from"+client);                    }                    if(key.isWritable()){                        SocketChannel client = (SocketChannel) key.channel();                        ByteBuffer byteBuffer = (ByteBuffer) key.attachment();                        while(byteBuffer.hasRemaining()){                            if(client.write(byteBuffer)==0){                                break;                            }                        }                        client.close();                    }                }catch (IOException ex){                    key.cancel();                    try {                        key.channel().close();                    }catch (IOException cex){                    }                }            }        }    }}

jdk的阻塞和非阻塞版本代码完全不同.

二,Netty

1,阻塞版

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 OioEventLoopGroup();        try{            ServerBootstrap b = new ServerBootstrap();            b.group(group)                    .channel(OioServerSocketChannel.class)                    .localAddress(new InetSocketAddress(port))                    .childHandler(new ChannelInitializer<SocketChannel>() {                        @Override                        protected void initChannel(SocketChannel socketChannel) throws Exception {                            socketChannel.pipeline().addLast(                                    new ChannelInboundHandlerAdapter(){                                        @Override                                        public void channelActive(ChannelHandlerContext ctx) throws Exception {                                            ctx.writeAndFlush(buf.duplicate()).addListener(ChannelFutureListener.CLOSE);                                        }                                    }                            );                        }                    });            ChannelFuture f = b.bind().sync();            f.channel().closeFuture().sync();        }finally {            group.shutdownGracefully().sync();        }    }}

2,非阻塞版

public class NettyNioServer {    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();   //1        try{            ServerBootstrap b = new ServerBootstrap();            b.group(group)                    .channel(NioServerSocketChannel.class)         //2                    .localAddress(new InetSocketAddress(port))                    .childHandler(new ChannelInitializer<SocketChannel>() {                        @Override                        protected void initChannel(SocketChannel socketChannel) throws Exception {                            socketChannel.pipeline().addLast(                                    new ChannelInboundHandlerAdapter(){                                        @Override                                        public void channelActive(ChannelHandlerContext ctx) throws Exception {                                            ctx.writeAndFlush(buf.duplicate()).addListener(ChannelFutureListener.CLOSE);                                        }                                    }                            );                        }                    });            ChannelFuture f = b.bind().sync();            f.channel().closeFuture().sync();        }finally {            group.shutdownGracefully().sync();        }    }}

阻塞版本和非阻塞版本只有1,2两处不一样.

与jdk相比,netty为没中传输实现都暴露了相同的API.无论选哪一种实现,代码几乎不受影响.