如何自動連接具有多個實現的接口

Question

我有3種公共方法的接口

public interface IUtil {
//public methods
}

我在一個抽象類中實現了兩種方法：

public abstract class PasswordUtil implements IUtil {

//implemented methods
}

和另一個班上的另一個

public abstract class EmailUtil implements IUtil  {
}

現在，我想自動連接接口，以便可以訪問My DAO類中的兩個實現的類，而DAO類在另一個包中。

    public  class RegistrationDAO  implements IRegistrationDAO {
        @Autowired
        IUtil util;
        @Autowired
        SessionFactory sessionFactory;
            } 

我在執行時遇到的錯誤是： Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}以下原因Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

異常堆棧跟蹤：

    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'xploreController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.service.IRegistrationService in.amruth.xplore.controller.XploreController.iregistrationservice; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'registrationservice': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.dao.IRegistrationDAO in.amruth.xplore.service.RegistrationService.iregistrationDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iregistrationDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4939)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5434)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.service.IRegistrationService in.amruth.xplore.controller.XploreController.iregistrationservice; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'registrationservice': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.dao.IRegistrationDAO in.amruth.xplore.service.RegistrationService.iregistrationDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iregistrationDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 22 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'registrationservice': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.dao.IRegistrationDAO in.amruth.xplore.service.RegistrationService.iregistrationDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iregistrationDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:957)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 24 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.dao.IRegistrationDAO in.amruth.xplore.service.RegistrationService.iregistrationDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iregistrationDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 35 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iregistrationDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1014)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:957)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 37 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: in.amruth.xplore.utility.IUtil in.amruth.xplore.dao.RegistrationDAO.util; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: 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$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:508)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    ... 48 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [in.amruth.xplore.utility.IUtil] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1100)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:960)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:855)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:480)
    ... 50 more

Answer 1

您的問題不是您有兩個實現，而是您沒有一個實現。

您只有無法實例化的抽象實現，因此無法在任何地方注入。

Answer 2

正如一些評論所指出的那樣，您不能實例化抽象類進行注入。 當自動裝配的目標可以解析到多個實例時，您需要使用限定符給出提示。

范例：

public  class RegistrationDAO  implements IRegistrationDAO {
    @Autowired
    @Qualifier("email")
    IUtil util;
    @Autowired
    SessionFactory sessionFactory;
} 

您的beans.xml具有這些Bean實例的限定符：

<beans>
    <bean class="PasswordUtil">
        <qualifier value="password" />
    </bean>
    <bean class="EmailUtil">
        <qualifier value="email" />
    </bean>
</beans>

參見Spring 3.2.2參考手冊的第5.9.3章