关于netty的简单实现

1. 新建两个maven项目, 分别为

netty-server: netty的服务端: 消息的消费者

netty-client: netty的客户端: 消息的生产者

2. 分别引入netty的maven依赖

 <dependency>
     <groupId>io.netty</groupId>
     <artifactId>netty-all</artifactId>
     <version>4.1.6.Final</version>
 </dependency>

3. netty-server服务端

3.1. 服务端引导类

 public class EchoServer {

     private int port;

     private EchoServer(int port) {
         this.port = port;
     }

     private void start() throws Exception {
         System.out.println("Echo Server Start");
         EventLoopGroup group = new NioEventLoopGroup();
         try {
             ServerBootstrap b = new ServerBootstrap();
             b.group(group)
                     .channel(NioServerSocketChannel.class)
                     .localAddress(new InetSocketAddress(port))
                     .childHandler(new ChannelInitializer<SocketChannel>() {
                         @Override
                         public void initChannel(SocketChannel ch) throws Exception {
                             ch.pipeline().addLast(new EchoServerHandler());
                         }
                     });
             ChannelFuture f = b.bind().sync();
             System.out.println("Server Start Listen At: " + port);
             f.channel().closeFuture().sync();
         } finally {
             group.shutdownGracefully();
         }
     }

     public static void main(String[] args) throws Exception {
         int port;
         if (args.length > 0) {
             port = Integer.parseInt(args[0]);
         } else {
             port = 8080;
         }
         new EchoServer(port).start();
     }
 }

3.2. 服务端消息消费业务

 public class EchoServerHandler extends ChannelInboundHandlerAdapter {

     @Override
     public void channelRead(ChannelHandlerContext ctx, Object msg) {
         ByteBuf bb = (ByteBuf) msg;
         bb.markReaderIndex();
         System.out.println("Server Received: " + ByteBufUtil.hexDump(bb.readBytes(bb.readableBytes())));
         bb.resetReaderIndex();
         ctx.write(msg);
     }

     @Override
     public void channelReadComplete(ChannelHandlerContext ctx) {
         ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
     }

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

4. netty-client客户端

4.1. 客户端引导类

 public class EchoClient {
     private String host;
     private int port;

     private EchoClient(String host, int port) {
         this.host = host;
         this.port = port;
     }

     private void start() throws Exception {
         System.out.println("Echo Client Start");
         EventLoopGroup group = new NioEventLoopGroup();
         try {
             Bootstrap b = new Bootstrap();
             b.group(group)
                     .channel(NioSocketChannel.class)
                     .remoteAddress(new InetSocketAddress(host, port))
                     .handler(new ChannelInitializer<SocketChannel>() {
                         @Override
                         public void initChannel(SocketChannel ch) throws Exception {
                             ch.pipeline().addLast(new EchoClientHandler());
                         }
                     });

             ChannelFuture f = b.connect().sync();
             System.out.println("Server Client Listen Host: [" + host + "] And Port: [" + port + "]");
             f.channel().closeFuture().sync();
         } finally {
             group.shutdownGracefully();
         }
     }

     public static void main(String[] args) throws Exception {
         String host = "127.0.0.1";
         int port = 8080;
         int len = 2;
         if (args.length == len) {
             host = args[0];
             port = Integer.parseInt(args[1]);
         }

         new EchoClient(host, port).start();
     }

 }

4.2 客户端消息生产业务

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        ctx.writeAndFlush(Unpooled.copiedBuffer("Netty Rocks!", CharsetUtil.UTF_8));
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, ByteBuf in) {
        System.out.println("Client Received: " + ByteBufUtil.hexDump(in.readBytes(in.readableBytes())));
    }

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

5. 测试:

5.1. 启动服务端

5.2. 启动客户端

5.3. 再看服务端