Netty客户端断线重连服务端

Netty客户端重连机制

 场景：
 1.Netty初次启动客户端，如果无法连接到服务端，将尝试重连。
 2.在客户端与服务端保持长连接的过程中，如果连接断开，尝试与服务端重连。

1. 主要代码

    Netty客户端启动处理类

   @Service("nettyClient")
   public class NettyClient {
   	private final static Logger log = LoggerFactory.getLogger(NettyClient.class);
   	private EventLoopGroup loop = new NioEventLoopGroup();
   	
   	@Autowired
   	private NettyFilter nettyFilter;
   	
   	@Autowired
   	private AppConfig appConfig;
   	
   	public void run(){
   		doConnect(new Bootstrap(), loop);
   	}
   
   	/**
   	 * netty client 连接，连接失败10秒后重试连接
   	 */
   	public void doConnect(Bootstrap bootstrap, EventLoopGroup eventLoopGroup) {
   		ChannelFuture f = null;
   		try {
   			if (bootstrap != null) {
   				bootstrap.group(eventLoopGroup);
   				bootstrap.channel(NioSocketChannel.class);
   				bootstrap.option(ChannelOption.SO_KEEPALIVE, true);
   				bootstrap.handler(nettyFilter);
   				bootstrap.remoteAddress(appConfig.getHost(), appConfig.getPort());
   				f = bootstrap.connect().addListener((ChannelFuture futureListener)->{
   					final EventLoop eventLoop = futureListener.channel().eventLoop();
   					if (!futureListener.isSuccess()) {
   						log.warn("客户端已启动，与服务端建立连接失败,10s之后尝试重连!");
   						eventLoop.schedule(() -> doConnect(new Bootstrap(), eventLoop), 10, TimeUnit.SECONDS);
   					}else {
   						log.info("客户端已启动成功,port:{}，开始登录服务端",appConfig.getPort());
   					    // 可以在这发送登录成功的消息给server
   					    //futureListener.channel().writeAndFlush(Unpooled.copiedBuffer("msg!!!", CharsetUtil.UTF_8));
   
   					}
   				});
   			}
   		} catch (Exception e) {
   			log.error("连接客户端失败,error：" + e);
   		}
   	}
   }
   

    客户端与服务端心跳处理类，与客户端断开连接后的重试代码在channelInactive()这个方法中

   @Service("idleclienthandler")
   @ChannelHandler.Sharable
   public class IdleClientHandler extends SimpleChannelInboundHandler<MessageBase> {
   	private final static Logger logger = LoggerFactory.getLogger(IdleClientHandler.class);
   	private long heartbeatCount = 0;
   	
   	@Autowired
   	private NettyClient nettyClient;
   
   
   	@Override
   	public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
   		if (evt instanceof IdleStateEvent) {
   			IdleStateEvent event = (IdleStateEvent) evt;
   		 	logger.info(ctx.channel().remoteAddress() + "，超时类型：" + event.state());
   			sendPingMsg(ctx);
   		} else {
   			super.userEventTriggered(ctx, evt);
   		}
   	}
   
   	/**
   	 * 发送ping消息
   	 * @param context
   	 */
   	protected void sendPingMsg(ChannelHandlerContext context) {
   		MessageBase body = NettyMessage.MessageBase.newBuilder()
   				.setCmd(CommandType.PING)
   				.setPtcode(Cache.ptcode)
   				.setData("ping")
   				.build();
   		context.writeAndFlush(body);
   		heartbeatCount++;
   		logger.info("Client sent ping msg to " + context.channel().remoteAddress() + ", count: " + heartbeatCount);
   	}
   
   	/**
   	 * 处理断开重连
   	 */
   	@SuppressWarnings("static-access")
   	@Override
   	public void channelInactive(ChannelHandlerContext ctx) throws Exception {
   		logger.info("与服务器连接断开，尝试重新连接...");
   		nettyClient.retryConnectFlag = true;
   		final EventLoop eventLoop = ctx.channel().eventLoop();  
   	    // 立即重连
   	    nettyClient.doConnect(new Bootstrap(), eventLoop);  
   		super.channelInactive(ctx);  
   	}
   
   	@Override
   	protected void channelRead0(ChannelHandlerContext ctx, MessageBase msg) throws Exception {
   		logger.info("收到的消息!{}",msg);
   	}
   }
   

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