Java activemq代理是什么意思？

我不熟悉

ActiveMQ

和

JMS

，并从探索helloworld程序的工作原理开始

我已经安装并运行了

ActiveMQ

server。现在，我创建了一个desctop应用程序并复制粘贴到其中。当我尝试运行它时，出现以下异常：

Caught: javax.jms.JMSException: Could not create Transport. Reason: javax.management.InstanceAlreadyExistsException: org.apache.activemq:BrokerName=localhost,Type=Broker
javax.jms.JMSException: Could not create Transport. Reason: javax.management.InstanceAlreadyExistsException: org.apache.activemq:BrokerName=localhost,Type=Broker
    at org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:35)
    at org.apache.activemq.ActiveMQConnectionFactory.createTransport(ActiveMQConnectionFactory.java:252)
    at org.apache.activemq.ActiveMQConnectionFactory.createActiveMQConnection(ActiveMQConnectionFactory.java:265)
    at org.apache.activemq.ActiveMQConnectionFactory.createActiveMQConnection(ActiveMQConnectionFactory.java:238)
    at org.apache.activemq.ActiveMQConnectionFactory.createConnection(ActiveMQConnectionFactory.java:184)
    at com.badmitrii.App$HelloWorldProducer.run(App.java:64)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.management.InstanceAlreadyExistsException: org.apache.activemq:BrokerName=localhost,Type=Broker
    at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:437)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900)
    at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324)
    at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)
    at org.apache.activemq.broker.jmx.ManagementContext.registerMBean(ManagementContext.java:366)
    at org.apache.activemq.broker.jmx.AnnotatedMBean.registerMBean(AnnotatedMBean.java:72)
    at org.apache.activemq.broker.BrokerService.startManagementContext(BrokerService.java:2370)
    at org.apache.activemq.broker.BrokerService.start(BrokerService.java:567)
    at org.apache.activemq.transport.vm.VMTransportFactory.doCompositeConnect(VMTransportFactory.java:124)
    at org.apache.activemq.transport.vm.VMTransportFactory.doConnect(VMTransportFactory.java:54)
    at org.apache.activemq.transport.TransportFactory.connect(TransportFactory.java:67)
    at org.apache.activemq.ActiveMQConnectionFactory.createTransport(ActiveMQConnectionFactory.java:250)
    ... 5 more

然后呢

Sent message: 386233378 : Thread-13
Sent message: 535117374 : Thread-16
Sent message: 1659874841 : Thread-17
Received: Hello world! From: Thread-17 : 56191182
Received: Hello world! From: Thread-16 : 1728802812
Received: Hello world! From: Thread-13 : 1191507779
Sent message: 1424811745 : Thread-22
Sent message: 1340394669 : Thread-25
Sent message: 1585379622 : Thread-29
Sent message: 607795742 : Thread-27
Sent message: 807925334 : Thread-32
Received: Hello world! From: Thread-22 : 1629703769
Received: Hello world! From: Thread-29 : 2145661378
Received: Hello world! From: Thread-25 : 1459121566
Received: Hello world! From: Thread-27 : 1628632972
Received: Hello world! From: Thread-32 : 538611977
Received: null

---

我的问题是，在那个例子中，我真的需要ActiveMQ服务器吗？例外情况中提到的

ActiveMQ代理是什么？
我想，您只需要ActiveMQ all-？.jar。这个例子本身就可以做到这一点。如果ActiveMQ服务器已启动，则可以停止它。启动“Hello ActiveMQ”应用程序后，您可能不会看到异常。但最好是插入

睡眠（3000）//我与异常的斗争（无法创建传输）

在创建第一个消费者之前。
我认为，您所需要的只是activemq all-？.jar。这个例子本身就可以做到这一点。如果ActiveMQ服务器已启动，则可以停止它。启动“Hello ActiveMQ”应用程序后，您可能不会看到异常。但最好是插入

睡眠（3000）//我与异常的斗争（无法创建传输）

在创建第一个使用者之前