【发布时间】:2011-12-12 06:13:09
【问题描述】:
我正在编写一个简单的教程。我有一个发布者发送关于某个主题的消息,而订阅者则接收它。当我启动应用程序时,弹簧配置文件加载,然后我收到以下错误
2011-10-20 21:50:39,340 DEBUG [org.springframework.jms.support.destination.JndiDestinationResolver] - Located object with JNDI name [RateTopic]
2011-10-20 21:50:39,340 DEBUG [org.springframework.jms.support.destination.JndiDestinationResolver] - Located object with JNDI name [RateTopic]
2011-10-20 21:50:39,340 DEBUG [org.springframework.jms.connection.CachingConnectionFactory] - Closing cached Session: ActiveMQSession {id=ID:Reverb0253-PC-62259-1319161839013-0:1:3,started=true}
2011-10-20 21:50:39,340 DEBUG [org.springframework.jms.connection.CachingConnectionFactory] - Closing cached Session: ActiveMQSession {id=ID:Reverb0253-PC-62259-1319161839013-0:1:2,started=true}
2011-10-20 21:50:44,348 WARN [org.springframework.jms.listener.DefaultMessageListenerContainer] - Setup of JMS message listener invoker failed for destination 'RateTopic' - trying to recover. Cause: Destination [RateTopic] is not of expected type [javax.jms.Queue]
org.springframework.jms.support.destination.DestinationResolutionException: Destination [RateTopic] is not of expected type [javax.jms.Queue]
at org.springframework.jms.support.destination.JndiDestinationResolver.validateDestination(JndiDestinationResolver.java:147)
at org.springframework.jms.support.destination.JndiDestinationResolver.resolveDestinationName(JndiDestinationResolver.java:112)
at org.springframework.jms.support.destination.JmsDestinationAccessor.resolveDestinationName(JmsDestinationAccessor.java:100)
at org.springframework.jms.listener.AbstractPollingMessageListenerContainer.createListenerConsumer(AbstractPollingMessageListenerContainer.java:221)
at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.initResourcesIfNecessary(DefaultMessageListenerContainer.java:1081)
at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.invokeListener(DefaultMessageListenerContainer.java:1057)
at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.executeOngoingLoop(DefaultMessageListenerContainer.java:1050)
at org.springframework.jms.listener.DefaultMessageListenerContainer$AsyncMessageListenerInvoker.run(DefaultMessageListenerContainer.java:947)
at java.lang.Thread.run(Thread.java:722)
为什么spring认为应该是队列而不是topic
我的 jndi 文件是这样的
java.naming.factory.initial = org.apache.activemq.jndi.ActiveMQInitialContextFactory
java.naming.provider.url = tcp://localhost:61616
java.naming.security.principal=system
java.naming.security.credentials=manager
connectionFactoryNames = TopicCF
topic.RateTopic = RateTopic
spring 配置文件是
<bean id="jndiTemplate" class="org.springframework.jndi.JndiTemplate">
<property name="environment">
<props>
<prop key="java.naming.factory.initial">
org.apache.activemq.jndi.ActiveMQInitialContextFactory
</prop>
<prop key="java.naming.provider.url">tcp://localhost:61616</prop>
<prop key="java.naming.security.principal">system</prop>
<prop key="java.naming.security.credentials">manager</prop>
</props>
</property>
</bean>
<bean id="jndiTopicConnFactory" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiTemplate" ref="jndiTemplate"/>
<!-- JNDI name of connection factory as defined by provider -->
<property name="jndiName" value="TopicCF"/>
</bean>
<bean id="topicConnFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
<property name="targetConnectionFactory" ref="jndiTopicConnFactory"/>
<!-- Number of sessions that will be cached -->
<property name="sessionCacheSize" value="1"/>
</bean>
<bean id="destinationResolver" class="org.springframework.jms.support.destination.JndiDestinationResolver">
<property name="jndiTemplate" ref="jndiTemplate"/>
<property name="cache" value="true"/>
<!-- do not create a dynamic destination if the destination name is not found in JNDI -->
<property name="fallbackToDynamicDestination" value="false"/>
</bean>
<bean id="messageListener" class="com.merc.springjmspubsublenderborrower.TBorrower"/>
<bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
<property name="connectionFactory" ref="topicConnFactory"/>
<property name="destinationResolver" ref="destinationResolver"/>
<property name="concurrentConsumers" value="3" />
<property name="destinationName" value="RateTopic"/>
<property name="messageListener" ref="messageListener" />
<property name="sessionAcknowledgeModeName" value="AUTO_ACKNOWLEDGE"/>
</bean>
我的订阅者实现 MessageListener
@Override
public void onMessage(Message message) {
try {
// Get the data from the message
BytesMessage msg = (BytesMessage) message;
double newRate = msg.readDouble();
// If the rate is at least 1 point lower than the current rate, then
//recommend refinancing
if ((currentRate - newRate) >= 1.0) {
System.out.println(
"New rate = " + newRate + " - Consider refinancing loan");
} else {
System.out.println("New rate = " + newRate + " - Keep existing loan");
}
System.out.println("\nWaiting for rate updates...");
} catch (Exception ex) {
ex.printStackTrace(System.out);
System.exit(1);
}
}
public static void main(String argv[]) {
ApplicationContext ctx = new ClassPathXmlApplicationContext("app-context.xml");
try {
// Run until enter is pressed
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
System.out.println("TBorrower application started");
System.out.println("Press enter to quit application");
stdin.readLine();
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
【问题讨论】:
-
在主题模式中,不要将
concurrentConsumers设置为大于1。 Spring 说:不要为一个主题增加并发消费者的数量。这将导致同一消息的并发消费,这几乎是不可取的。 -
主题的全部意义在于拥有多个消费者。这样多个进程都可以得到相同的消息。
-
晚会,但多元消费理念是为了区分消费者。这样如果消息符合其利益,则每个消费者都会计算/