netty开发入门代码

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NettyServer 端 服务端

public class NettyServer {
	public static void main(String[] args) throws Exception{
		NettyServer.start();
	}
	public static void start() throws Exception{
		final NettyServerHandler serverHandler = new NettyServerHandler();
		EventLoopGroup bossGroup = new NioEventLoopGroup();
		EventLoopGroup workGroup = new NioEventLoopGroup();
		try {
			ServerBootstrap b = new ServerBootstrap();
			b.group(bossGroup,workGroup).channel(NioServerSocketChannel.class)
			.option(ChannelOption.SO_BACKLOG,1024)//设置TCP缓冲区
			.childHandler(new ChannelInitializer<Channel>() {
				@Override
				protected void initChannel(Channel ch) throws Exception {
					// TODO Auto-generated method stub
					ch.pipeline().addLast(serverHandler);
				}
			});
			ChannelFuture f = b.bind(8000).sync();
			f.channel().closeFuture().sync();
		}finally {
			bossGroup.shutdownGracefully().sync();
			workGroup.shutdownGracefully().sync();
		}
	}
}

建立连接时，会调用channelHandler接口实现类，这里就是个人自定义实现逻辑的地方；其他代码都是模板方法

serverHandler

public class NettyServerHandler extends ChannelInboundHandlerAdapter{
 
	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
		// TODO Auto-generated method stub
		ByteBuf in = (ByteBuf)msg;
		byte[] req = new byte[in.readableBytes()];
		in.readableBytes();
		System.out.println("sever received:" + in.toString(CharsetUtil.UTF_8));
		ctx.write(in);
	}
	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
		// TODO Auto-generated method stub
		ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
	}
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
		// TODO Auto-generated method stub
		cause.printStackTrace();
		ctx.close();
	}
	
}

 channelHandler接口方法比较多，其实我们主要用的就是chanelRead，exceptionCaught方法等。其他的可以交给别的实现类去执行。

nettyClient端

public class NettyClientServer {
  public static void main(String[] args) throws Exception{
	  NettyClientServer.start();
}
  public static void start()throws Exception{
	  EventLoopGroup group = new NioEventLoopGroup();
	  try {
		  Bootstrap b = new Bootstrap();
		  b.group(group).channel(NioSocketChannel.class)
		  .remoteAddress(new InetSocketAddress("127.0.0.1",8000))
		  .handler(new ChannelInitializer<Channel>() {
			  protected void initChannel(Channel ch) throws Exception {
				  ch.pipeline().addLast(new NettyClientServerHandler());
				  
			  };
		});
		  ChannelFuture f = b.connect().sync();
		  f.channel().closeFuture().sync();
	  }finally {
		  group.shutdownGracefully().sync();
	  }
  }
}

clientHandler,客户端连接成功后，会触发channelHandler接口实现类中的激活方法channelActive,此时与服务器之间的连接建立成功；

public class NettyClientServerHandler extends SimpleChannelInboundHandler<ByteBuf>{

	@Override
	protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {
		// TODO Auto-generated method stub
		System.out.println("client received:" + msg.toString(CharsetUtil.UTF_8));
	}
	 @Override
	public void channelActive(ChannelHandlerContext ctx) throws Exception {
		 ByteBuf message = null;
		 for(int i= 0 ; i<100;i++) {
			 message = Unpooled.buffer("Netty rocks!".getBytes().length);
			 message.writeBytes("Netty rocks!".getBytes());
			 ctx.writeAndFlush(message);
		 }
	}
	 @Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
		cause.printStackTrace();
		ctx.close();
	}
}