问题排查 Active Scheduler of name 'MyClusterScheduler' already registered in Quartz SchedulerRepository.

一、Error日志&原因

最近在搞Springboot整合Quartz2.3.0的时候遇到了一个诡异的问题，工程启动不起来。

错误log:

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'schedulerFactoryBean' defined in class path resource [com/nana/matrix/timer/quartz/QuartzConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: Active Scheduler of name 'MyClusterScheduler' already registered in Quartz SchedulerRepository. Cannot create a new Spring-managed Scheduler of the same name!
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1803)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:874)
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:778)
	... 47 common frames omitted
Caused by: java.lang.IllegalStateException: Active Scheduler of name 'MyClusterScheduler' already registered in Quartz SchedulerRepository. Cannot create a new Spring-managed Scheduler of the same name!
	at org.springframework.scheduling.quartz.SchedulerFactoryBean.createScheduler(SchedulerFactoryBean.java:679)
	at org.springframework.scheduling.quartz.SchedulerFactoryBean.prepareScheduler(SchedulerFactoryBean.java:614)
	at org.springframework.scheduling.quartz.SchedulerFactoryBean.afterPropertiesSet(SchedulerFactoryBean.java:502)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1862)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1799)
	... 58 common frames omitted

排查了很久，以为是配置文属性配置的不对，或者是工程内另外一个类QuartzDemo代码影响的。结果，发现都不是。没办法，就断点debug，查看quartz源码，最终发现了问题出现的根本原因。

根本原因是：

工程里面我的quartz的配置文件名为quartz.properties，跟Quartz默认的配置文件名quartz.properties相同。导致工程启动的时候，我本地的quartz配置文件覆盖了系统的配置文件。工程启动时，首先进入QuartzInitializerListener.java，执行了contextInitialized()方法，并实例化了一个Scheduler。随后，进入QuartzConfig.java中执行了 schedulerFactoryBean()方法，并在在执行

propertiesFactoryBean.getObject();后进入SchedulerFactoryBean.java类中，执行了

afterPropertiesSet()
prepareSchedulerFactory()
createScheduler(SchedulerFactory schedulerFactory, @Nullable String schedulerName)

从而再一次实例化了一个相同的Scheduler，导致Scheduler实例化了两次，所以报Error：