Netty5.0 实现心跳包

这是一个netty自带的echo案例，添加了心跳包的设置而已，关键代码如下：

/*
 * 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 io.netty.example.echo;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.util.SelfSignedCertificate;
import io.netty.handler.timeout.IdleStateHandler;

/**
 * Echoes back any received data from a client.
 */
public final class EchoServer {

	static final boolean SSL = System.getProperty("ssl") != null;
	static final int PORT = Integer
			.parseInt(System.getProperty("port", "8007"));

	public static void main(String[] args) throws Exception {
		// Configure SSL.
		final SslContext sslCtx;
		if (SSL) {
			SelfSignedCertificate ssc = new SelfSignedCertificate();
			sslCtx = SslContext.newServerContext(ssc.certificate(),
					ssc.privateKey());
		} else {
			sslCtx = null;
		}

		// Configure the server.
		EventLoopGroup bossGroup = new NioEventLoopGroup(1);
		EventLoopGroup workerGroup = new NioEventLoopGroup();
		try {
			ServerBootstrap b = new ServerBootstrap();
			b.group(bossGroup, workerGroup)
					.channel(NioServerSocketChannel.class)
					.option(ChannelOption.SO_BACKLOG, 100)
					.handler(new LoggingHandler(LogLevel.INFO))
					.childHandler(new ChannelInitializer<SocketChannel>() {
						@Override
						public void initChannel(SocketChannel ch)
								throws Exception {
							ChannelPipeline p = ch.pipeline();
							if (sslCtx != null) {
								
								p.addLast(sslCtx.newHandler(ch.alloc()));
							}
							// p.addLast(new LoggingHandler(LogLevel.INFO));
							p.addLast("idleStateHandler", new IdleStateHandler(10, 5, 0));
					                p.addLast("myHandler", new MyHandler());
							p.addLast(new EchoServerHandler());
						}
					});

			// Start the server.
			ChannelFuture f = b.bind(PORT).sync();

			// Wait until the server socket is closed.
			f.channel().closeFuture().sync();
		} finally {
			// Shut down all event loops to terminate all threads.
			bossGroup.shutdownGracefully();
			workerGroup.shutdownGracefully();
		}
	}
}

package io.netty.example.echo;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;

/**
 * @Project : netty
 * @Package : io.netty.example.echo
 * @Class : MyHandler
 * @Company 广州讯动网络科技有限公司
 * @Author : 蔡文锋
 * @DateTime：2015年4月21日 下午11:15:47
 * @Blog：http://blog.csdn.net/caiwenfeng_for_23
 * @Description : {
 *  Handler should handle the IdleStateEvent triggered by IdleStateHandler.
 * }
 *
 */
public class MyHandler extends ChannelHandlerAdapter {
	@Override
	public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
			throws Exception {
		if (evt instanceof IdleStateEvent) {
			IdleStateEvent e = (IdleStateEvent) evt;
			if (e.state() == IdleState.READER_IDLE) {
				ctx.close();
				System.out.println("READER_IDLE 读超时");
			} else if (e.state() == IdleState.WRITER_IDLE) {
				ByteBuf buff = ctx.alloc().buffer();
				buff.writeBytes("mayi test".getBytes());
				ctx.writeAndFlush(buff);
				System.out.println("WRITER_IDLE 写超时");
			}
		}
	}
}

首先添加了idleStateHandler用于监听链接idle，如果连接到达idle时间，这个handler会触发idleEvent，之后通过重写userEventTriggered方法，完成idle事件的处理。

可以用telnet进行测试：

telnet 127.0.0.1 8007

测试结果：

WRITER_IDLE 写超时
READER_IDLE 读超时