在運行時創建Spring Bean

Question

我正在嘗試使用@Configuration和@Bean批注在運行時創建bean。 原因是我試圖讓Spring了解所創建的bean，以便它可以處理正在創建的應用程序的調度。 我已經定義了帶注釋的類，如下所示：

@Configuration  
public class GathererConfigBean {
    @Bean(name = "FactoryBean")
    public MethodInvokingJobDetailFactoryBean createMethodInvokingJobDetail(String service, Object obj, String method) throws ClassNotFoundException, NoSuchMethodException{
        MethodInvokingJobDetailFactoryBean jobDetailFactory = new MethodInvokingJobDetailFactoryBean();
        jobDetailFactory.setBeanName(service + "FactoryBean");
        jobDetailFactory.setTargetObject(obj);
        jobDetailFactory.setTargetMethod(method);
        jobDetailFactory.setConcurrent(false);
        jobDetailFactory.afterPropertiesSet();
        return jobDetailFactory;
    }

    @Bean(name = "TriggerBean")
    public CronTriggerBean createTriggerBean(String service, JobDetail job, String schedule) throws ParseException{
        CronTriggerBean trigger = new CronTriggerBean();
        trigger.setBeanName(service + "TriggerBean");
        trigger.setJobDetail(job);
        trigger.setCronExpression(schedule);
        return trigger;
    }

    public CronTrigger createTrigger(String service, JobDetail job, String schedule) throws ParseException{
        return createTriggerBean(service, job, schedule);
    }

    public JobDetail createJobDetail(String service, AbstractGatherer obj, String method) throws ClassNotFoundException, NoSuchMethodException{
        return (JobDetail) createMethodInvokingJobDetail(service, obj, method).getObject();
    }
}

問題是，當我運行此程序時，總是會遇到以下異常，並且無法找到類似的在線示例。 最初，我以為這是因為它們具有相同的名稱，但事實並非如此，因為當我只運行一個時，會遇到相同的錯誤。

    Exception in thread "main" org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'FactoryBean' defined in class path resource [com/linuxbox/enkive/statistics/gathering/GathererConfigBean.class]: Unsatisfied dependency expressed through constructor argument with index 0 of type [java.lang.String]: : No matching bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
Related cause: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'FactoryBean': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:730)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:461)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:983)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:879)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:563)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
    at com.linuxbox.enkive.Main.run(Main.java:54)
    at com.linuxbox.enkive.MainJettyWebApps.main(MainJettyWebApps.java:53)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [java.lang.String] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:920)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:789)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:703)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:795)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:723)
    ... 16 more
Related cause:
org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'FactoryBean': Requested bean is currently in creation: Is there an unresolvable circular reference?
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.beforeSingletonCreation(DefaultSingletonBeanRegistry.java:297)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:216)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getTypeForFactoryBean(AbstractBeanFactory.java:1343)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:678)
    at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:507)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:317)
    at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:185)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:829)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:786)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:703)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:795)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:723)
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:461)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:983)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:879)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:291)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:288)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:190)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:563)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:895)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:425)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
    at com.linuxbox.enkive.Main.run(Main.java:54)
    at com.linuxbox.enkive.MainJettyWebApps.main(MainJettyWebApps.java:53)

任何幫助，反饋，想法或建議將不勝感激，如果您需要更多具體信息，請告訴我！

Answer 1

我建議您對依賴注入執行后需要執行的一種方法使用@PostConstruct批注。 查看此鏈接以了解更多信息。

另一種方法是使您的類實現ApplicationContextAware接口來訪問應用程序上下文。 有關更多詳細信息，請參考此鏈接。

希望這對您有所幫助。 干杯。

Answer 2

看來spring難以解決Bean方法的String參數。 看看spring文檔 ，他們在其中使用JavaConfig構造數據源。 如示例所示，您應該嘗試使用@Qualifier

@Autowired @Qualifier("quartz.service.name") String service;
// ...

或帶有SpEL表達式的@Value綁定字符串參數

@Value("${quartz.service.name"}) String service;

Spring文檔未提供將@Autowired @Qualifier用作JavaConfig的方法參數注釋的示例，但應與構造函數自動裝配一致。