Netty IdleStateHandler 出现问题 - 我是否以错误的方式测试它？

Question

我有一个玩具 Netty 服务器，当客户端的通道上没有发生任何事情时，我试图向客户端发送心跳消息。我正在通过远程登录到服务器、写入消息然后不发送任何内容来测试这一点，但我没有收到任何消息！

控制台：

>>telnet localhost 6969
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
>>foo
Did you say 'foo'?

MyPipelineFactory.java

public class MyPipelineFactory implements ChannelPipelineFactory {
    private final Timer timer;
    private static final ChannelHandler stringDecoder = new StringDecoder();
    private static final ChannelHandler stringEncoder = new StringEncoder();
    private final ChannelHandler idleStateHandler;

    public MyPipelineFactory(Timer t) {
        this.timer = t;
        this.idleStateHandler = new IdleStateHandler(timer, 5, 5, 5);
    }

    public ChannelPipeline getPipeline() {
        // create default pipeline from static method
        ChannelPipeline pipeline = Channels.pipeline();
        pipeline.addLast("idleStateHandler", this.idleStateHandler); // heartbeat
        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(1024, Delimiters.lineDelimiter()));
        //pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1024,0,1)); // get header from message
        pipeline.addLast("stringDecoder", stringDecoder);
        pipeline.addLast("stringEncoder", stringEncoder);
        pipeline.addLast("ServerHandler", new ServerHandler()); // goes at the end

        return pipeline;
    }
}

HeartbeatHandler.java

public class HeartbeatHandler extends IdleStateAwareChannelHandler {

    @Override
    public void channelIdle(ChannelHandlerContext ctx, IdleStateEvent e) {
        if (e.getState() == IdleState.READER_IDLE) {
            System.out.println("Reader idle, closing channel");
            //e.getChannel().close();
            e.getChannel().write("heartbeat-reader_idle");
        }
        else if (e.getState() == IdleState.WRITER_IDLE) {
            System.out.println("Writer idle, sending heartbeat");
            e.getChannel().write("heartbeat-writer_idle");
        }
        else if (e.getState() == IdleState.ALL_IDLE) {
            System.out.println("All idle, sending heartbeat");
            e.getChannel().write("heartbeat-all_idle");
        }
    }
}

---

已修复：

我忘记了 HeartbeatHandler，它需要 IdleStateHandler（这部分对我来说并不明显）。那行得通。

public class MyPipelineFactory implements ChannelPipelineFactory {
    private final Timer timer;
    private static final ChannelHandler stringDecoder = new StringDecoder();
    private static final ChannelHandler stringEncoder = new StringEncoder();
    private final ChannelHandler idleStateHandler;
    private final ChannelHandler heartbeatHandler;

    public MyPipelineFactory(Timer t) {
        this.timer = t;
        this.idleStateHandler = new IdleStateHandler(timer, 5, 5, 5);
        this.heartbeatHandler = new HeartbeatHandler();
    }

    public ChannelPipeline getPipeline() {
        // create default pipeline from static method
        ChannelPipeline pipeline = Channels.pipeline();
        pipeline.addLast("idleStateHandler", this.idleStateHandler);
        pipeline.addLast("heartbeatHandler", this.heartbeatHandler); // heartbeat
        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(1024, Delimiters.lineDelimiter()));
        //pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1024,0,1)); // get header from message
        pipeline.addLast("stringDecoder", stringDecoder);
        pipeline.addLast("stringEncoder", stringEncoder);
        pipeline.addLast("ServerHandler", new ServerHandler()); // goes at the end

        return pipeline;
    }
}

Answer 1

您错过了在 ChannelPipeline 中添加 HeartbeatHandler。您需要将 IdleStateHandler AND HeartbeatHandler 添加到 ChannelPipeline 才能使其工作。

Answer 2

Norman的回答确实很有帮助，但我想指出另一件事：idleStateHandler和heartbeatHandler应该是特定于通道的，因此在PipeLineFactory中，您不应该将这两个处理程序构造为私有成员，而是需要创建getPipeline() 方法中的新内容。你还有一个通道映射来保存构建的通道，如果你需要释放它们，你最好也停止计时器来释放资源。