Java bayeux 客户端在空闲时与 TimeoutException 断开连接

Question

我正在初始化 Bayeux 客户端：

SslContextFactory sslContextFactory = new SslContextFactory(true);

HttpClient httpClient = new HttpClient(sslContextFactory);

httpClient.start();

Map<String, Object> options = new HashMap<String, Object>();

ClientTransport transport = new LongPollingTransport(options, httpClient);

BayeuxClient client =  new BayeuxClient("https://localhost:8483/cometd/", transport);

client.handshake();

boolean handshaken = client.waitFor(20000, BayeuxClient.State.CONNECTED);

if (!handshaken) {

    LOGGER.info("Failed to handshake");

    throw new RuntimeException("Failed to handshake");

}

我用它与服务器进行一些通信，它可以工作，它订阅频道、发送、接收，然后我让它闲置一段时间。我得到以下异常：

java.util.concurrent.TimeoutException: Idle timeout 20000 ms

at org.eclipse.jetty.client.http.HttpConnectionOverHTTP.onIdleExpired(HttpConnectionOverHTTP.java:145)

at org.eclipse.jetty.io.ssl.SslConnection.onIdleExpired(SslConnection.java:286)

at org.eclipse.jetty.io.AbstractEndPoint.onIdleExpired(AbstractEndPoint.java:401)

at org.eclipse.jetty.io.IdleTimeout.checkIdleTimeout(IdleTimeout.java:166)

at org.eclipse.jetty.io.IdleTimeout$1.run(IdleTimeout.java:50)

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)

at java.util.concurrent.FutureTask.run(FutureTask.java:266)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)

at java.lang.Thread.run(Thread.java:748)

Answer 1

事实证明，我阻塞了 cometD 线程：我构建了一个命令行工具来检查服务器，当我收到一条消息（带有来自 cometD 的线程）时，我持有该线程以供用户输入。如果我持有该线程足够长的时间，cometD 将与上述异常断开连接。解决方案：当你收到 CometD 的消息时，不要持有它，使用新线程。

Answer 2

默认心跳由服务器端timeout参数控制，默认为30秒。这意味着当系统空闲时，长轮询每 30 秒发生一次。您已idleTimeout在 20 秒时配置了客户端，这从您的异常堆栈跟踪中可以明显看出。当系统空闲时，客户端将在心跳（长轮询）响应之前超时连接，导致您看到的错误。将客户端配置为idleTimeout大于心跳的值就足够了timeout，或者 - 等效地 - 将心跳设置timeout为小于客户端的值idleTimeout。