Java 为什么在服务器和客户端网络中总是调用channelActive方法

我正在使用下面的工作示例。这可能是一堵“代码墙”，但问题很简单：为什么总是调用方法

channelActive

？如果您不想阅读代码，也可以在这里找到示例

净周期客户：

public class NettyClient {

    private String host;
    private int port = 5000;

    public NettyClient(String host) {
        this.host = host;
    }

    public void send() throws InterruptedException {

        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
            .channel(NioSocketChannel.class)
            .option(ChannelOption.TCP_NODELAY, true)
            .handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel ch) throws Exception {

                    ChannelPipeline p = ch.pipeline();
                    p.addLast(new ObjectEncoder());
                    p.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));
                    p.addLast(new NettyClientHandler());
                }
            });

            ChannelFuture future = b.connect(host, port).sync();

            future.channel().closeFuture().sync();
        } finally {
            group.shutdownGracefully();
        }
    }

}

NettyServer

public class NettyServer extends Thread{

    private Logger logger = LoggerFactory.getLogger(getClass());

    private int port = 5000;

    public NettyServer() {
    }

    @Override
    public void run() {

        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
            .channel(NioServerSocketChannel.class)
            .option(ChannelOption.SO_BACKLOG, 1024)
            .childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                public void initChannel(SocketChannel ch) throws Exception {

                    ChannelPipeline p = ch.pipeline();
                    p.addLast(new ObjectEncoder());
                    p.addLast(new ObjectDecoder(Integer.MAX_VALUE, ClassResolvers.cacheDisabled(null)));
                    p.addLast(new NettyServerHandler());
                }
            });

            // Bind and start to accept incoming connections.
            ChannelFuture f = b.bind(port).sync(); // (7)

            logger.info("server bind port:{}", port);

            // Wait until the server socket is closed.
            f.channel().closeFuture().sync();

        } catch (InterruptedException e) {
            logger.info(e.getMessage());
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

}

当我尝试从客户机->服务器写入时，我总是将其作为putput

客户端：

Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client

和服务器端：

2019-09-25 20:43:34.688  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:34.984  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.268  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.571  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.855  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.137  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.468  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.777  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.072  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.364  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.648  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.930  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.214  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.503  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.797  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler 

---

我们至少可以说客户端已连接到服务器。：）

每次接受新连接时都会调用channelActive

。我怀疑您在从客户端写入服务器时创建了新连接

对。但是，当连接出现时，我应该怎么做？我试着写，但什么也没发生。你需要调用

writeAndFlush（…）

然后是。当我调用

send（）

时，客户端的一个通道将激活，服务器的一个通道将激活。然后客户端通道完全关闭。返回的通道的状态如何？您检查了它是否失败了吗？现在我已经停止使用Netty，而是使用RESTAPI HTTP。我发现Netty很难使用。很抱歉但为了回答你们的问题，我并没有得到任何返回状态。似乎当我从客户机打开一个通道并直接发送时，服务器就打开了一个到的通道。但是服务器没有收到该消息。如果你想看看我的解决方案。请查收：

        // Start the Netty server
        try {
            new NettyServer().start();
            logger.info("Starting netty server");
        } catch (Exception e) {
            logger.info(e.getMessage());
        }

Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client
Channel active - client

2019-09-25 20:43:34.688  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:34.984  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.268  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.571  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:35.855  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.137  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.468  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:36.777  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.072  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.364  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.648  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:37.930  INFO 8639 --- [ntLoopGroup-3-1] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.214  INFO 8639 --- [ntLoopGroup-3-2] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.503  INFO 8639 --- [ntLoopGroup-3-3] s.d.J.netty.NettyServerHandler           : Channel active - server
2019-09-25 20:43:38.797  INFO 8639 --- [ntLoopGroup-3-4] s.d.J.netty.NettyServerHandler