apache-camel - 为什么ActiveMQ 5.14.x无法启动嵌入camel-jms组件2.18.3

Question

下面是一个简单的spring boot项目(版本1.5.2)来演示这个问题:

https://github.com/lanwen/camel-jms-activemq-test

它有 Apache Camel 版本 2.18.3

在分行 master一切正常，因为 activemq-camel=5.14.4和 camel-jms=2.16.3 (从它传递)

Spring boot 应用程序以日志正常启动:

2017-04-22 00:53:19.647  INFO 97217 --- [           main] o.a.camel.spring.SpringCamelContext      : Apache Camel 2.18.3 (CamelContext: camel-1) is starting
2017-04-22 00:53:19.662  INFO 97173 --- [           main] o.apache.activemq.broker.BrokerService   : Apache ActiveMQ 5.14.4 (localhost, ID:lanwen-osx3.local-62145-1492811599544-0:1) is starting
2017-04-22 00:53:19.665  INFO 97173 --- [           main] o.apache.activemq.broker.BrokerService   : Apache ActiveMQ 5.14.4 (localhost, ID:lanwen-osx3.local-62145-1492811599544-0:1) started
2017-04-22 00:53:19.665  INFO 97173 --- [           main] o.apache.activemq.broker.BrokerService   : For help or more information please see: http://activemq.apache.org
2017-04-22 00:53:19.682  INFO 97173 --- [           main] o.a.activemq.broker.TransportConnector   : Connector vm://localhost started
2017-04-22 00:53:19.702  INFO 97173 --- [           main] o.a.camel.spring.SpringCamelContext      : Route: route1 started and consuming from: activemq://queue:to-write?asyncConsumer=true
2017-04-22 00:53:19.703  INFO 97173 --- [           main] o.a.camel.spring.SpringCamelContext      : Total 1 routes, of which 1 are started.
2017-04-22 00:53:19.704  INFO 97173 --- [           main] o.a.camel.spring.SpringCamelContext      : Apache Camel 2.18.3 (CamelContext: camel-1) started in 0.466 seconds
2017-04-22 00:53:19.709  INFO 97173 --- [           main] ru.yandex.test.writer.MyTestApplication  : Started MyTestApplication in 2.437 seconds (JVM running for 2.911)

但是当你从 camel-jms=2.18.3 开始时(作为camel的主版本，在分支 not_working上)

此日志出现问题:

2017-04-22 00:56:38.070  INFO 97195 --- [           main] o.a.camel.spring.SpringCamelContext      : Apache Camel 2.18.3 (CamelContext: camel-1) is starting
...
2017-04-22 00:56:43.590  WARN 97195 --- [ActiveMQ Task-1] o.a.a.t.failover.FailoverTransport       : Failed to connect to [tcp://localhost:61616] after: 10 attempt(s) continuing to retry.

但是如果我们改变 activemq-camel至 5.13.4与 camel-jms=2.18.3它再次正常工作......

为什么使用 ActiveMQ 5.14.x 不适用于 Camel jms 2.18.x ?

Answer 1

如果您查看最新 Camel ActiveMQ 的依赖项列表 1.15.5 ( https://mvnrepository.com/artifact/org.apache.activemq/activemq-camel/5.14.5 )，你会看到它已经有了 camel-jms作为依赖项，但版本是 1.16.3 .因此，您无需单独添加 camel-jms 1.18.x POM 中的依赖项，因为它会覆盖 1.16.x ActiveMQ 已经使用的版本，这是兼容的版本。

所以本质上，问题在于您正在尝试使用更新的、不兼容的 camel-jms 版本。 .当您单独添加 1.18.x 时camel-jms依赖，ActiveMQ 组件网将使用此版本，该版本与其 1.16.x 不兼容版本，因此，错误。

如果您需要使用 ActiveMQ，那么您可能需要查看 camel-jms 1.16.x会为你工作。