com.zhuang.netty.handler.heartbeat.HeartbeatClientHandler Maven / Gradle / Ivy

Go to download
package com.zhuang.netty.handler.heartbeat;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

@Slf4j
public class HeartbeatClientHandler extends ChannelInboundHandlerAdapter {

    private static final ByteBuf HEARTBEAT_SEQUENCE = Unpooled.unreleasableBuffer(Unpooled.copiedBuffer("HEARTBEAT", CharsetUtil.UTF_8));

    private static final int HEARTBEAT_INTERVAL_SECONDS = 10;

    private ScheduledFuture heartBeatTask;

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        // 定时向服务器发送心跳消息
        heartBeatTask = ctx.executor().scheduleAtFixedRate(
                new HeartbeatTask(ctx), 0, HEARTBEAT_INTERVAL_SECONDS, TimeUnit.SECONDS);
        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        heartBeatTask.cancel(true);
        super.channelInactive(ctx);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        if (msg instanceof ByteBuf && ((ByteBuf) msg).equals(HEARTBEAT_SEQUENCE)) {
            // 收到服务器的心跳响应消息
            log.info("Client receive heartbeat response");
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        if (heartBeatTask != null) {
            heartBeatTask.cancel(true);
            heartBeatTask = null;
        }
        ctx.fireExceptionCaught(cause);
    }

    private static class HeartbeatTask implements Runnable {

        private final ChannelHandlerContext ctx;

        public HeartbeatTask(ChannelHandlerContext ctx) {
            this.ctx = ctx;
        }

        @Override
        public void run() {
            ctx.writeAndFlush(HEARTBEAT_SEQUENCE.duplicate());
            log.info("Client send heartbeat");
        }

    }
}