Netty IdleStateHandler出現問題 - 我測試了錯誤的方法嗎？

Question

我有一個玩具Netty服務器，並試圖發送心跳消息給客戶端，當他們的頻道沒有發生任何事情時。我正在通過telnet到服務器，寫信息然後不發送任何東西來測試這個，但是我沒有聽到任何信息！

控制檯：

>>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"); 
     } 
    } 
} 

---

修正：

我忘了有HeartbeatHandler，它需要IdleStateHandler（這部分對我來說並不明顯）。這樣可行。

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

您錯過了在ChannelPipeline中添加HeartbeatHandler。您需要將IdleStateHandler 和 HeartbeatHandler添加到ChannelPipeline以使其工作。

Answer 2

Norman的回答是一個非常有用的，但我想指出另一件事情：idleStateHandler和heartbeatHandler應該是通道特定的，所以在PipeLineFactory中，您不應該將這兩個處理程序構造爲私有成員，但需要在getPipeline（）方法中創建新的。您還可以通過頻道圖保存構建的頻道，如果您需要發佈頻道，最好還是停止計時器以釋放資源。