netty入门（1）

public static void main(String[] args) {
    String host = "127.0.0.1";
    int port = 8886;
    EventLoopGroup group = new NioEventLoopGroup();

    try {
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioSocketChannel.class)
                .handler(new MyClientInitializer());

        // 启动客户端.
        ChannelFuture f = b.connect(host, port).sync();
        f.channel().closeFuture().sync();

    } catch (InterruptedException e) {
        e.printStackTrace();
    } finally {
        group.shutdownGracefully();
    }
}

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());
    }
}
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("msg:"+msg);
        ctx.writeAndFlush("from client:" + LocalDateTime.now());
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush("from client:" + "我主动发第一条数据");
    }

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

public class MyServer {
    int port ;

    public MyServer(int port){
        this.port = port;
    }

    public void start() throws Exception{
        EventLoopGroup boss = new NioEventLoopGroup(); // selector
        EventLoopGroup work = new NioEventLoopGroup(); // channel
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(boss,work)
                    .handler(new LoggingHandler(LogLevel.DEBUG))
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new MyServerInitializer());

            ChannelFuture f = bootstrap.bind(new InetSocketAddress(port)).sync();
            System.out.println(" server start up on port : " + port);
            f.channel().closeFuture().sync();
        } finally {
            boss.shutdownGracefully();
            work.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception{
        MyServer server = new MyServer(8899);// 8081为启动端口
        server.start();
    }
}

public class    MyServerInitializer extends ChannelInitializer<SocketChannel> {
    // 客户端一旦和服务端连接，这个方法就会被调用
    @Override
    protected void initChannel(SocketChannel channel) throws Exception {
        ChannelPipeline pipeline = channel.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 MyRequestHandler());
    }
}

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

}