netty-心跳处理器

服务器

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap()
                    .group(bossGroup,workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))//在bossGroup增加一个日志处理器
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            //加入一个netty提供的IdleStateHandler(处理空闲状态的处理器)
                            //参数1：多久没有读，就会发送一个心跳检测包，检测是否连接
                            //参数2：多久没有写，就会发送一个心跳检测包，检测是否连接
                            //参数3：多久既没有读也没有写，就会发送一个心跳检测包，检测是否连接
                            pipeline.addLast(new IdleStateHandler(3,5,7, TimeUnit.SECONDS));
                            //加入一个对空间检测进一步处理的自定义handler
                            //当IdleStateHandler的IdleStateEvent触发后，
                            // 就会通过pipeline传给下一个handler的userEventTiggered方法
                            pipeline.addLast(new MyServerHandler());
                        }
                    });
            ChannelFuture cf = serverBootstrap.bind(7000).sync();
            cf.channel().closeFuture().sync();
        }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }

自定义处理器

public class MyServerHandler extends ChannelInboundHandlerAdapter {

    /**
     *
     * @param ctx 上下文
     * @param evt 事件
     * @throws Exception
     */
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        if (evt instanceof IdleStateEvent){
            IdleStateEvent event = (IdleStateEvent) evt;
            //判断空闲类型
            String type = null;
            switch (event.state()){
                case READER_IDLE:
                    type = "读空闲";
                    break;
                case WRITER_IDLE:
                    type = "写空闲";
                    break;
                case ALL_IDLE:
                    type = "读写空闲";
            }
            System.out.println(ctx.channel().remoteAddress()+"发生事件："+type);
        }
    }
}

注意：如果连接断开，将不会发生空闲