netty基本用法

public class HelloClient {
	public static String host = "127.0.0.1";
	     public static int port = 7878;
	 
	     /**
	      * @param args
	      * @throws InterruptedException 
	      * @throws IOException 
	      */
	     public static void main(String[] args) throws InterruptedException, IOException {
	         EventLoopGroup workGroup = new NioEventLoopGroup();
	         try {
	             Bootstrap b = new Bootstrap();
	             b.group(workGroup)
	             .channel(NioSocketChannel.class)
	             .handler(new HelloClientInitializer());
	 
	             // 连接服务端
	             ChannelFuture future = b.connect(host, port).sync();
	             
	             // 控制台输入
	             BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
	             for (;;) {
	                 String line = in.readLine();
	                 if (line == null) {
	                     continue;
	                 }
	                 /*
	                  * 向服务端发送在控制台输入的文本 并用"\r\n"结尾
	                  * 之所以用\r\n结尾 是因为我们在handler中添加了 DelimiterBasedFrameDecoder 帧解码。
	                  * 这个解码器是一个根据\n符号位分隔符的解码器。所以每条消息的最后必须加上\n否则无法识别和解码
	                  * */
	                 future.channel().writeAndFlush(line + "\r\n");
	             }
	         } finally {
	             // The connection is closed automatically on shutdown.
	        	 workGroup.shutdownGracefully();
	         }
	     }
}

public class HelloClientInitializer extends ChannelInitializer<SocketChannel> {
	
	     protected void initChannel(SocketChannel ch) throws Exception {
	         ChannelPipeline pipeline = ch.pipeline();
	 
	         /*
	          * 这个地方的 必须和服务端对应上。否则无法正常解码和编码
	          * 
	          * 解码和编码 我将会在下一张为大家详细的讲解。再次暂时不做详细的描述
	          * 
	          * */
	         pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
	         pipeline.addLast("decoder", new StringDecoder());
	         pipeline.addLast("encoder", new StringEncoder());
	         
	         // 客户端的逻辑
	         pipeline.addLast("handler", new HelloClientHandler());
	    }

}

public class HelloClientHandler extends SimpleChannelInboundHandler<String> {
	     @Override
	     protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
         
	         System.out.println("Server say : " + msg);
	     }
	     
	     @Override
	     public void channelActive(ChannelHandlerContext ctx) throws Exception {
	         System.out.println("Client active ");
	         super.channelActive(ctx);
	     }
	 
	     @Override
	     public void channelInactive(ChannelHandlerContext ctx) throws Exception {
	         System.out.println("Client close ");
	         super.channelInactive(ctx);
	     }
}

public class HelloServer {
	 /**
     * 服务端监听的端口地址
     */
    private static final int portNumber = 7878;
    
    public static void main(String[] args) throws InterruptedException {
    	//第一个线程组用于接收client连接
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        //第二个线程组用于具体的业务处理
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
        	//创建一个辅助类Boosatrap用于对Server进行一系列的配置
            ServerBootstrap b = new ServerBootstrap();
            //将两个线程组加入进来
            b.group(bossGroup, workerGroup);
            //指定使用NioServerSocketChannel这种类型的通道
            b.channel(NioServerSocketChannel.class);
            //一定要使用childHandler绑定具体的事件处理器
            b.childHandler(new HelloServerInitializer());
            
            //SocketChannel通道的配置项（保持连接）
            b.option(ChannelOption.SO_KEEPALIVE, true);
            
            // 服务器绑定端口监听
            ChannelFuture f = b.bind(portNumber).sync();
            // 监听服务器关闭监听
            f.channel().closeFuture().sync();

            // 可以简写为
            /* b.bind(portNumber).sync().channel().closeFuture().sync(); */
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

public class HelloServerInitializer extends ChannelInitializer<SocketChannel> {
	     @Override
	     protected void initChannel(SocketChannel ch) throws Exception {
	         ChannelPipeline pipeline = ch.pipeline();
	 
	         // 以("\n")为结尾分割的 解码器
	         pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
	 
	         // 字符串解码 和 编码
	         pipeline.addLast("decoder", new StringDecoder());
	         pipeline.addLast("encoder", new StringEncoder());
 
	         // 自己的逻辑Handler
	         pipeline.addLast("handler", new HelloServerHandler());
	     }
}

public class HelloServerHandler extends SimpleChannelInboundHandler<String> {
	     @Override
	     protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
	         // 收到消息直接打印输出
	         System.out.println(ctx.channel().remoteAddress() + " Say : " + msg);
	         
	         // 返回客户端消息 - 我已经接收到了你的消息
	         ctx.writeAndFlush("Received your message !\n");
	     }
	     
	     /*
	      * 
	      * 覆盖 channelActive 方法 在channel被启用的时候触发 (在建立连接的时候)
	      * 
	      * channelActive 和 channelInActive 在后面的内容中讲述，这里先不做详细的描述
	      * */
	     @Override
	     public void channelActive(ChannelHandlerContext ctx) throws Exception {
	         
	         System.out.println("RamoteAddress : " + ctx.channel().remoteAddress() + " active !");
	         
	         ctx.writeAndFlush( "Welcome to " + InetAddress.getLocalHost().getHostName() + " service!\n");
	         
	         super.channelActive(ctx);
	     }
}