spring boot netty 即时通讯系统之心跳机制（七）_usereventtriggered

  netty心跳机制，通过userEventTriggered方法进行心跳检测，用户超时长时间未操作时则会触发，通过发送ping/pong的指令来保持客户端与服务端之间的连接不中断，推荐从前面的章节开始看。

HeartBeatReqHandler.java
 
import com.alibaba.fastjson.JSONObject;
import com.fyrt.fyrtim.util.*;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import lombok.extern.slf4j.Slf4j;
 
 
/**
 * 心跳检测 客户端
 */
@Slf4j
public class HeartBeatReqHandler extends SimpleChannelInboundHandler {
 
 
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        NettyMessage nettyMessage= (NettyMessage) JsonUtil.parseNettyMessage(msg);
        if (LoginUtil.hasLogin(ctx.channel())) {
            if (TransportType.HEARTBEAT.getValue().equals(nettyMessage.getTransportType())) {
                if (nettyMessage.getMsg().equals("pong")) {
                    log.info("收到pong请求");
                    log.info("发送ping请求");
                    ctx.writeAndFlush(JSONObject.toJSONString(new NettyMessage(TransportType.HEARTBEAT.getValue(), "ping", ctx.channel())));
                } else if (nettyMessage.getMsg().equals("ok")) {
                    log.info("心跳续约:" + nettyMessage.getMsg());
                }
            }else{
                //直接跳转到下个handler请求
                ctx.fireChannelRead(msg);
            }
        } else {
            //直接跳转到下个handler请求
            ctx.fireChannelRead(msg);
        }
    }
 
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, Object o) throws Exception {
 
    }
 
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        //直接跳转到下个handler请求
        ctx.fireChannelActive();
    }
 
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        //退出登录
        UserChannelUtil.unBindUser(ctx.channel());
        LoginUtil.logoOut(ctx.channel());
        System.out.println("客户端已关闭");
    }
 
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object obj) throws Exception {
        if (obj instanceof IdleStateEvent){
            IdleStateEvent event = (IdleStateEvent)obj;
            if (event.state()== IdleState.READER_IDLE){
                log.info("客户端读超时");
            }else if (event.state()== IdleState.WRITER_IDLE){
                log.info("客户端写超时");
            }else if (event.state()==IdleState.ALL_IDLE){
                log.info("客户端所有操作超时");
            }
            ctx.writeAndFlush(JSONObject.toJSONString(new NettyMessage(TransportType.HEARTBEAT.getValue(),"ping",ctx.channel())));
        }
 
    }
}

HeartBeatRespHandler.java
 
import com.alibaba.fastjson.JSONObject;
import com.fyrt.fyrtim.util.JsonUtil;
import com.fyrt.fyrtim.util.NettyMessage;
import com.fyrt.fyrtim.util.TransportType;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import lombok.extern.slf4j.Slf4j;
 
/**
 * 心跳检测 服务端
 */
@Slf4j
public class HeartBeatRespHandler extends SimpleChannelInboundHandler {
 
 
 
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
 
 
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        NettyMessage nettyMessage = (NettyMessage) JsonUtil.parseNettyMessage(msg);
        if (nettyMessage.isLogin()){
            if (TransportType.HEARTBEAT.getValue().equals(nettyMessage.getTransportType())) {
                log.info("收到客户端pong请求");
                log.info("发送ping请求");
                ctx.writeAndFlush(JSONObject.toJSONString(new NettyMessage(TransportType.HEARTBEAT.getValue(), "ok", ctx.channel())));
            }else{
                ctx.fireChannelRead(msg);
            }
        }else{
            ctx.fireChannelRead(msg);
        }
    }
 
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, Object o) throws Exception {
 
    }
 
 
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        //退出登录
        System.out.println("服务端已关闭");
    }
 
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object obj) throws Exception {
        if (obj instanceof IdleStateEvent){
            IdleStateEvent event = (IdleStateEvent)obj;
            if (event.state()== IdleState.READER_IDLE){
                log.info("客户端读超时");
            }else if (event.state()== IdleState.WRITER_IDLE){
                log.info("客户端写超时");
            }else if (event.state()==IdleState.ALL_IDLE){
                log.info("客户端所有操作超时");
            }
        }
 
    }
}

 实现效果：

代码已上传至github:https://github.com/beibeirenzhe/netty-im/tree/master/fyrtim