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

1 <dependency>
2     <groupId>io.netty</groupId>
3     <artifactId>netty-all</artifactId>
4     <version>4.1.6.Final</version>
5 </dependency>

3. netty-server服务端

3.1. 服务端引导类

 1 public class EchoServer {
 2 
 3     private int port;
 4 
 5     private EchoServer(int port) {
 6         this.port = port;
 7     }
 8 
 9     private void start() throws Exception {
10         System.out.println("Echo Server Start");
11         EventLoopGroup group = new NioEventLoopGroup();
12         try {
13             ServerBootstrap b = new ServerBootstrap();
14             b.group(group)
15                     .channel(NioServerSocketChannel.class)
16                     .localAddress(new InetSocketAddress(port))
17                     .childHandler(new ChannelInitializer<SocketChannel>() {
18                         @Override
19                         public void initChannel(SocketChannel ch) throws Exception {
20                             ch.pipeline().addLast(new EchoServerHandler());
21                         }
22                     });
23             ChannelFuture f = b.bind().sync();
24             System.out.println("Server Start Listen At: " + port);
25             f.channel().closeFuture().sync();
26         } finally {
27             group.shutdownGracefully();
28         }
29     }
30 
31     public static void main(String[] args) throws Exception {
32         int port;
33         if (args.length > 0) {
34             port = Integer.parseInt(args[0]);
35         } else {
36             port = 8080;
37         }
38         new EchoServer(port).start();
39     }
40 }

3.2. 服务端消息消费业务

 1 public class EchoServerHandler extends ChannelInboundHandlerAdapter {
 2 
 3     @Override
 4     public void channelRead(ChannelHandlerContext ctx, Object msg) {
 5         ByteBuf bb = (ByteBuf) msg;
 6         bb.markReaderIndex();
 7         System.out.println("Server Received: " + ByteBufUtil.hexDump(bb.readBytes(bb.readableBytes())));
 8         bb.resetReaderIndex();
 9         ctx.write(msg);
10     }
11 
12     @Override
13     public void channelReadComplete(ChannelHandlerContext ctx) {
14         ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
15     }
16 
17     @Override
18     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
19         cause.printStackTrace();
20         ctx.close();
21     }
22 }

4. netty-client客户端

4.1. 客户端引导类

 1 public class EchoClient {
 2     private String host;
 3     private int port;
 4 
 5     private EchoClient(String host, int port) {
 6         this.host = host;
 7         this.port = port;
 8     }
 9 
10     private void start() throws Exception {
11         System.out.println("Echo Client Start");
12         EventLoopGroup group = new NioEventLoopGroup();
13         try {
14             Bootstrap b = new Bootstrap();
15             b.group(group)
16                     .channel(NioSocketChannel.class)
17                     .remoteAddress(new InetSocketAddress(host, port))
18                     .handler(new ChannelInitializer<SocketChannel>() {
19                         @Override
20                         public void initChannel(SocketChannel ch) throws Exception {
21                             ch.pipeline().addLast(new EchoClientHandler());
22                         }
23                     });
24 
25             ChannelFuture f = b.connect().sync();
26             System.out.println("Server Client Listen Host: [" + host + "] And Port: [" + port + "]");
27             f.channel().closeFuture().sync();
28         } finally {
29             group.shutdownGracefully();
30         }
31     }
32 
33     public static void main(String[] args) throws Exception {
34         String host = "127.0.0.1";
35         int port = 8080;
36         int len = 2;
37         if (args.length == len) {
38             host = args[0];
39             port = Integer.parseInt(args[1]);
40         }
41 
42         new EchoClient(host, port).start();
43     }
44 
45 }

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