Cumulocity 實施新協議

Question

我正在研究跟蹤器代理並嘗試添加一個新協議以與我的設備一起使用。 我試圖模仿你對 GL200 協議所做的事情，但是當它到達 TrackerFactory.create() 時，它返回以下錯誤：

16:05:47.912 [pool-2-thread-1] ERROR c8y.trackeragent.RequestHandler - Error handling request:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'connectedAXTracker': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected java.util.List c8y.trackeragent.ConnectedTracker.fragments; nested exception is org.springframework.beans.factory.NoSuchBeanDefinition
Exception: No qualifying bean of type [c8y.trackeragent.Fragment] found for dependency [collection of c8y.trackeragent.Fragment]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1202) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:217) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:350) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:331) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at c8y.trackeragent.protocol.mapping.TrackerFactory.create(TrackerFactory.java:76) ~[classes/:na]
        at c8y.trackeragent.protocol.mapping.TrackerFactory.discoverTracker(TrackerFactory.java:48) ~[classes/:na]
        at c8y.trackeragent.protocol.mapping.TrackerFactory.getTracker(TrackerFactory.java:33) ~[classes/:na]
        at c8y.trackeragent.RequestHandler.run(RequestHandler.java:32) ~[classes/:na]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_91]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_91]
        at java.lang.Thread.run(Thread.java:745) [na:1.8.0_91]
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected java.util.List c8y.trackeragent.ConnectedTracker.fragments; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [c8y.trackeragent.Fragment] found for dependency [collection of c8y.trackeragent.Fragment]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:561) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        ... 14 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [c8y.trackeragent.Fragment] found for dependency [collection of c8y.trackeragent.Fragment]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1308) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]

        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1006) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:949) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:533) ~[spring-beans-4.1.4.RELEASE.jar:4.1.4.RELEASE]
        ... 16 common frames omitted

我對 Spring 一無所知，你能給我一個提示嗎？

Answer 1

我發現了問題：我擴展 AXFragment 接口（本身擴展 Fragment）的類沒有被標記為 @Component。

Answer 2

僅從堆棧跟蹤中就發生了這種情況：它發現連接的跟蹤器屬於您添加的類型，但是在嘗試實例化類時失敗，因為它無法設置該類所需的片段列表。

每個跟蹤器協議至少需要有一個片段（一個實現 c8y.trackeragent.Fragment 的類）。

如果您查看 GL200 實現，則有另一個接口 GL200Fragment，然后例如解析器 (GL200Parser) 實現該接口。 看起來您沒有添加任何實現此接口的類。