我有一个（相当）复杂的Java应用程序，它使用Camel（2.11.0）和ActiveMQ（5.8.0）在Camel路由和各种ActiveMQ队列之间发送消息。我正在使用的Camel-ActiveMQ端点定义了故障转移，如下所示：
failover:(tcp://myBroker01.example.com:61616)?jms.prefetchPolicy.queuePrefetch=1&randomize=false&maxReconnectDelay=250
你会注意到我只定义了1个经纪人;现在我只有1个代理（因此这种方式取消了故障转移传输的有用性），但在此之后我可能会有几个代理作为此故障转移URI的一部分。
当我运行我的应用时，我在应用日志中看到以下错误：
org.apache.camel.CamelExecutionException: Exception occurred during execution on the exchange: Exchange[Message: <com.me.myapp.model.WidgetVO>
...middle portion of stack trace omitted for brevity; probably irrelevant
Caused by: javax.jms.JMSException: Unexpected failure.
at org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:62)
at org.apache.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:1409)
at org.apache.activemq.ActiveMQConnection.ensureConnectionInfoSent(ActiveMQConnection.java:1496)
at org.apache.activemq.ActiveMQConnection.createSession(ActiveMQConnection.java:325)
at org.apache.activemq.pool.ConnectionPool$2.makeObject(ConnectionPool.java:105)
at org.apache.activemq.pool.ConnectionPool$2.makeObject(ConnectionPool.java:90)
at org.apache.commons.pool.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:1220)
at org.apache.activemq.pool.ConnectionPool.createSession(ConnectionPool.java:142)
at org.apache.activemq.pool.PooledConnection.createSession(PooledConnection.java:174)
at org.springframework.jms.support.JmsAccessor.createSession(JmsAccessor.java:196)
at org.springframework.jms.core.JmsTemplate.execute(JmsTemplate.java:457)
... 76 more
Caused by: java.io.IOException: Unexpected failure.
at org.apache.activemq.transport.failover.FailoverTransport.oneway(FailoverTransport.java:620)
at org.apache.activemq.transport.MutexTransport.oneway(MutexTransport.java:68)
at org.apache.activemq.transport.ResponseCorrelator.asyncRequest(ResponseCorrelator.java:81)
at org.apache.activemq.transport.ResponseCorrelator.request(ResponseCorrelator.java:86)
at org.apache.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:1380)
... 85 more
因此，看起来Camel正在正确读取我的故障转移传输配置，并尝试异步发送（oneway(...)）序列化WidgetVO消息到我的队列。我搜索了GrepCode for line 620 of FailoverTransport，这里是抛出异常的代码块：
if (transport == null) {
// Previous loop may have exited due to use being
// disposed.
if (disposed) {
error = new IOException("Transport disposed.");
} else if (connectionFailure != null) {
error = connectionFailure;
} else if (timedout == true) {
error = new IOException("Failover timeout of " + timeout + " ms reached.");
} else {
error = new IOException("Unexpected failure.");
}
break;
}
所以Transport为NULL，但是消息没有被标记为处理，也没有连接失败，我们与代理的连接也没有超时。
这对任何人都有意义吗？谁能给我一些关于如何开始调试的指示？如果需要，我很乐意发布更多代码。
更新：这是我在应用程序日志之前中看到的另一条警告消息：
07:53:00,306 WARN [DefaultJmsMessageListenerContainer] Rejecting received message because of
the listener container having been stopped in the meantime: ActiveMQTextMessage {commandId
= 7, responseRequired = true, messageId = ID:<myserver.example.com>, originalDestination = null,
originalTransactionId = null, producerId = ID:<myserver.example.com>, destination = queue://myQueue,
transactionId = null, expiration = 0, timestamp = 1392295980294, arrival = 0,
brokerInTime = 1392295980297, brokerOutTime = 1392295980298, correlationId = null, replyTo = null,
persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0,
targetConsumerId = null, compressed = false, userID = null, content = null,
marshalledProperties = org.apache.activemq.util.ByteSequence@2d0b20f5, dataStructure = null,
redeliveryCounter = 0, size = 0, properties = {breadcrumbId=ID-<myserver.example.com>},
readOnlyProperties = true, readOnlyBody = true, droppable = false, text = <com.me.myapp.WidgetVO>
...WidgetVO>}
出于安全考虑，我显然必须将所有服务器名称更改为<myserver.example.com>。我认为有趣的是transactionId是NULL ...