Netty的基本使用

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Netty的基本使用

服务端定义

开启服务端端口

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public class MyServer {
    public static void main(String[] args) {
        EventLoopGroup boseGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            // handler 只针对boseGroup
            // childHandler 经过boseGroup后再经过workerGroup
            serverBootstrap.group(boseGroup,workerGroup).channel(NioServerSocketChannel.class)
                    .childHandler(new MyServerInitializer());
            ChannelFuture channelFuture = serverBootstrap.bind(8899).sync();
            channelFuture.channel().closeFuture().sync();


        }catch (Exception e) {
            e.printStackTrace();
        }finally {
            boseGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

定义服务端initialize

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public class MyServerInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,4,0,4));
        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyHttpServerHandler());
    }
}

定义服务端handler

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public class MyHttpServerHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println(ctx.channel().remoteAddress() + ", " + msg);
        ctx.channel().writeAndFlush("from server "+ UUID.randomUUID());
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

客户端定义

绑定客户端端口和ip

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public class MyClient {
    public static void main(String[] args) {
        EventLoopGroup eventExecutors = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventExecutors).channel(NioSocketChannel.class)
                .handler(new MyClientInitializer());
            ChannelFuture localhost = bootstrap.connect("localhost", 8899).sync();
            localhost.channel().closeFuture().sync();

        }catch (Exception e) {
            e.printStackTrace();
        }finally {
            eventExecutors.shutdownGracefully();
        }
    }
}

定义客户端initialize

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public class MyClientInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,4,0,4));
        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
        pipeline.addLast(new MyClientHandler());
    }
}

定义客户端handler

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public class MyClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println(ctx.channel().remoteAddress());
        System.out.println("client ouput: " + msg);
        ctx.channel().writeAndFlush("from client:"+ LocalDateTime.now());
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush("来自于客户端的问候!");
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}