Java tutorial
/* * Copyright 2013-2018 Lilinfeng. * * Licensed 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.zhaopeng.timeserver.protocol.netty.client; import com.zhaopeng.timeserver.protocol.netty.MessageType; import com.zhaopeng.timeserver.protocol.netty.struct.Header; import com.zhaopeng.timeserver.protocol.netty.struct.NettyMessage; import io.netty.channel.ChannelHandlerAdapter; import io.netty.channel.ChannelHandlerContext; import java.util.concurrent.ScheduledFuture; import java.util.concurrent.TimeUnit; /** * Created by zhaopeng on 2016/10/19. */ public class HeartBeatReqHandler extends ChannelHandlerAdapter { private volatile ScheduledFuture<?> heartBeat; public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { NettyMessage message = (NettyMessage) msg; // ????? if (message.getHeader() != null && message.getHeader().getType() == MessageType.LOGIN_RESP.value()) { heartBeat = ctx.executor().scheduleAtFixedRate(new HeartBeatTask(ctx), 0, 5000, TimeUnit.MILLISECONDS); } else if (message.getHeader() != null && message.getHeader().getType() == MessageType.HEARTBEAT_RESP.value()) { System.out.println("Client receive server heart beat message : ---> " + message); } else ctx.fireChannelRead(msg); } private class HeartBeatTask implements Runnable { private final ChannelHandlerContext ctx; public HeartBeatTask(final ChannelHandlerContext ctx) { this.ctx = ctx; } @Override public void run() { NettyMessage heatBeat = buildHeatBeat(); System.out.println("Client send heart beat messsage to server : ---> " + heatBeat); ctx.writeAndFlush(heatBeat); } private NettyMessage buildHeatBeat() { NettyMessage message = new NettyMessage(); Header header = new Header(); header.setType(MessageType.HEARTBEAT_REQ.value()); message.setHeader(header); return message; } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); if (heartBeat != null) { heartBeat.cancel(true); heartBeat = null; } ctx.fireExceptionCaught(cause); } }