我正在尝试使用camel将消息从我的Web应用程序路由到队列，并且我使用bean引用从每当向浏览器提供输入时运行的函数中获取消息。但是，当camel继续轮询时会创建一个Null异常，因为每半秒都不会有输入。我怎样才能使骆驼只在有人拿起时才收到信息？ Browserbean是从浏览器返回消息的函数。
这是我的骆驼路线：
<camelContext xmlns="http://camel.apache.org/schema/spring">
<route>
<from uri="browserBean"/>
<to uri="jms:queue:testQSource"/>
<to uri="myBean"/>
<log message="Routing message from testQSource to testQDestination queue with data ${body}"/>
<to uri="jms:queue:testQDestination"/>
<to uri="finalBean"/>
<log message="message: ${body}"/>
</route>
</camelContext>
<camel:camelContext id="camel-client">
<camel:template id="camelTemplate" />
</camel:camelContext>
<bean id="jms" class="org.apache.activemq.camel.component.ActiveMQComponent">
<property name="brokerURL" value="tcp://localhost:61616" />
</bean>
<bean id="myBean" class="com.example.integration.modifier"/>
<bean id="finalBean" class="com.example.integration.ActionApp"/>
<bean id="browserBean" class="com.hello.integration.GreetingController"/>
</beans>
这是我每隔一秒左右得到的堆栈跟踪：
Message History
--------------------------------------------------------------------------------------- ------------------------------------------------
RouteId ProcessorId Processor Elapsed (ms)
[route1 ] [route1 ] [browserBean ] [ 0]
[route1 ] [to1 ] [jms:queue:testQSource ] [ 0]
Exchange
---------------------------------------------------------------------------------------------------------------------------------------
Exchange[
Id ID-CO183LTCS06-59664-1403735006145-0-16
ExchangePattern InOnly
Headers {breadcrumbId=ID-CO183LTCS06-59664-1403735006145-0-15, CamelRedelivered=false, CamelRedeliveryCounter=0}
BodyType null
Body [Body is null]
]
Stacktrace
--------------------------------------------------------------------------------------- ------------------------------------------------
java.lang.NullPointerException: null
at com.hello.integration.GreetingController.greeting(GreetingController.java:15)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.camel.component.bean.MethodInfo.invoke(MethodInfo.java:407)
at org.apache.camel.component.bean.MethodInfo$1.doProceed(MethodInfo.java:278)
at org.apache.camel.component.bean.MethodInfo$1.proceed(MethodInfo.java:251)
at org.apache.camel.component.bean.BeanProcessor.process(BeanProcessor.java:166)
at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:105)
at org.apache.camel.component.bean.BeanProcessor.process(BeanProcessor.java:67)
at org.apache.camel.impl.ProcessorPollingConsumer.receive(ProcessorPollingConsumer.java:58)
at org.apache.camel.impl.ProcessorPollingConsumer.receiveNoWait(ProcessorPollingConsumer.java: 66)
at org.apache.camel.impl.DefaultScheduledPollConsumer.poll(DefaultScheduledPollConsumer.java:4 8)
at org.apache.camel.impl.ScheduledPollConsumer.doRun(ScheduledPollConsumer.java:187)
at org.apache.camel.impl.ScheduledPollConsumer.run(ScheduledPollConsumer.java:114)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.runAndReset(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)