記錄一下我在安裝 canal-adapter1.1.14最新版本安裝的過程中出現的NullPointerException異常
以下是我的canal-adapter/logs文件夾內adapter.log文件的報錯日志，僅僅抽取報錯部分
2020-03-11 10:47:13.223 [main] ERROR c.a.o.canal.adapter.launcher.loader.CanalAdapterService - ## something goes wrong when starting up the canal client adapters: java.lang.NullPointerException: null at java.util.Hashtable.put(Hashtable.java:460) at com.alibaba.otter.canal.client.kafka.KafkaCanalConnector.<init>(KafkaCanalConnector.java:52) at com.alibaba.otter.canal.adapter.launcher.loader.CanalAdapterKafkaWorker.<init>(CanalAdapterKafkaWorker.java:38) at com.alibaba.otter.canal.adapter.launcher.loader.CanalAdapterLoader.init(CanalAdapterLoader.java:109) at com.alibaba.otter.canal.adapter.launcher.loader.CanalAdapterService.init(CanalAdapterService.java:58) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:365) at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:308) at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:135) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:422) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1694) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:579) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$1(AbstractBeanFactory.java:353) at org.springframework.cloud.context.scope.GenericScope$BeanLifecycleWrapper.getBean(GenericScope.java:390) at org.springframework.cloud.context.scope.GenericScope.get(GenericScope.java:184) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:350) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089) at org.springframework.cloud.context.scope.refresh.RefreshScope.eagerlyInitialize(RefreshScope.java:126) at org.springframework.cloud.context.scope.refresh.RefreshScope.start(RefreshScope.java:117) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.context.event.ApplicationListenerMethodAdapter.doInvoke(ApplicationListenerMethodAdapter.java:264) at org.springframework.context.event.ApplicationListenerMethodAdapter.processEvent(ApplicationListenerMethodAdapter.java:182) at org.springframework.context.event.ApplicationListenerMethodAdapter.onApplicationEvent(ApplicationListenerMethodAdapter.java:144) at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:400) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:354) at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:888) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:161) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) at com.alibaba.otter.canal.adapter.launcher.CanalAdapterApplication.main(CanalAdapterApplication.java:19)
我下載了源碼，然后根據報錯信息去跟蹤分析，
大致分析出來是getMqServers()這個方法在調用的時候，返回了空值，那我就去配置文件中去搜索“mq”，結果還真的有
在canal-adapter/conf文件夾下的application.yml文件中
終於發現這個不起眼的注釋，然后把這個注釋打開之后，再重新restart一下adapter，世界重新變得美好了。