Netty5.0---丢弃服务协议(DiscardServer)

DiscardServer.java

/* * Copyright 2012 The Netty Project * * The Netty Project licenses this file to you under the Apache License, * version 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at: * *   http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. */package com.netty.demo.discard;import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;/** * Discards any incoming data. * 丢弃服务协议，会忽略所有接收数据的协议 */public class DiscardServer {    private final int port;//端口        public DiscardServer(int port) {        this.port = port;    }    public void run() throws Exception {        EventLoopGroup bossGroup = new NioEventLoopGroup();//老板线程        EventLoopGroup workerGroup = new NioEventLoopGroup();//员工线程        try {        //创建一个ServerBootstrap实例 ,ServerBootstrap是Netty服务端的启动辅助类，它提供了一系列的方法用于设置服务端启动相关的参数            ServerBootstrap b = new ServerBootstrap();            b.group(bossGroup, workerGroup)             .channel(NioServerSocketChannel.class)             .childHandler(new ChannelInitializer<SocketChannel>() {                 @Override                 public void initChannel(SocketChannel ch) throws Exception {                 //业务处理                     ch.pipeline().addLast(new DiscardServerHandler());                 }             });            // Bind and start to accept incoming connections.            //绑定和开始接受进来的连接            ChannelFuture f = b.bind(port).sync();            // Wait until the server socket is closed.            // In this example, this does not happen, but you can do that to gracefully            //丢弃服务协议，什么都不会做            System.err.println("--------丢弃服务协议--------------");            // shut down your server//关闭服务            f.channel().closeFuture().sync();        } finally {        //始终都会执行的代码            workerGroup.shutdownGracefully();//关闭员工线程            bossGroup.shutdownGracefully();//关闭老板线程        }    }    public static void main(String[] args) throws Exception {        int port;        if (args.length > 0) {            port = Integer.parseInt(args[0]);        } else {            port = 8088;//运行出错，可能是端口被占用        }        new DiscardServer(port).run();//启动丢弃服务协议    }}

DiscardServerHandler.java

/* * Copyright 2012 The Netty Project * * The Netty Project licenses this file to you under the Apache License, * version 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at: * *   http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. */package com.netty.demo.discard;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;import java.util.logging.Level;import java.util.logging.Logger;/** * Handles a server-side channel. */public class DiscardServerHandler extends SimpleChannelInboundHandler<Object> {//日志    private static final Logger logger = Logger.getLogger(DiscardServerHandler.class.getName());    @Override    public void messageReceived(ChannelHandlerContext ctx, Object msg) throws Exception {        // discard    logger.info("---------消息接收器---------------");    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx,            Throwable cause) throws Exception {        // Close the connection when an exception is raised.    //当出现异常的时候，会关闭连接        logger.log(                Level.WARNING,                "Unexpected exception from downstream.",                cause);        logger.info("-------出现异常，关闭连接-------------");        ctx.close();    }}

下面是改进过的DiscardServerHandler.java，会相应telnet客户端 

在telnet 里输入什么就在服务端控制台输出什么（单字节输出）

package com.netty.demo.discard;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;import io.netty.util.ReferenceCountUtil;import java.util.logging.Level;import java.util.logging.Logger;/** * Handles a server-side channel. */public class DiscardServerHandler extends SimpleChannelInboundHandler<Object> {//日志    private static final Logger logger = Logger.getLogger(DiscardServerHandler.class.getName());    @Override    public void messageReceived(ChannelHandlerContext ctx, Object msg) throws Exception {        // discard        //自己改动过的，官网例子的这个方法没有任何东西的    logger.info("---------消息接收器---------------");    ByteBuf in=(ByteBuf) msg;    try {while(in.isReadable()){System.out.println("--yy--"+(char)in.readByte());System.out.flush();}} catch (Exception e) {// TODO Auto-generated catch block/** * 在netty5.0版本，不需要释放资源,框架已经自动帮我们释放, * 如果再加ReferenceCountUtil.release(msg)这句代码，运行就回报错 *///ReferenceCountUtil.release(msg);e.printStackTrace();}    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx,            Throwable cause) throws Exception {        // Close the connection when an exception is raised.    //当出现异常的时候，会关闭连接        logger.log(                Level.WARNING,                "Unexpected exception from downstream.",                cause);        logger.info("-------出现异常，关闭连接-------------");        ctx.close();    }}

运行效果图：