女士们和女士们，您好！
我正在实施一个系统，试图保持高度的灵活性。我们有一个称为EmailTaskService的抽象超类，它有两个继承自它的类。一个是EmailTaskServiceImpl（具体的实现类），另一个是另一个称为ScheduledEmailTaskService的抽象类，它具有一个称为ScheduledEmailTaskServiceImpl的子类。
为了保持灵活性，我们在ScheduledEmailTaskService上同时使用了垂直和水平装饰器模式。这意味着它继承自EmailTaskService以及组成具体服务本身。但是我的问题来自尝试自动连接具体的EmailTaskServiceImpl，我得到的只是抛出的No qualifying bean of type EmailTaskServiceImpl异常。显然，我不能仅仅自动连接EmailTaskService，因为它是一个抽象类，而不是一个接口。
我将在下面的代码中发布，以使您了解发生了什么。
EmailTaskService
public abstract class EmailTaskService<E, I> implements GenericService<E, I>{
@Autowired
protected EmailTaskDAO emailTaskDao;
public abstract void deleteEmailTask(I emailTaskId);
}
EmailTaskServiceImpl
@Service("emailTaskService")
public class EmailTaskServiceImpl extends EmailTaskService<EmailTask, Long>{
@Override
@Transactional
public long getTotalObjects() {
return super.emailTaskDao.count();
}
etc etc other methods here doing concretey things.
ScheduledEmailTaskService
public abstract class ScheduledEmailTaskService<E, I> extends EmailTaskService<E, I> {
@Autowired
protected ScheduledEmailTaskDAO scheduledEmailTaskDao;
@Autowired
@Qualifier("emailTaskService")
protected EmailTaskService<EmailTask, Long> emailTaskService;
@Override
public abstract void deleteEmailTask(I emailTaskId) throws InvalidInvocationException;
public abstract void deleteScheduledEmailTask(I scheduledEmailTaskId);
}
ScheduledEmailTaskService
@Service
public class ScheduledEmailTaskServiceImpl extends ScheduledEmailTaskService<ScheduledEmailTask, Long> {
@Override
@Transactional
public long getTotalObjects() {
return super.scheduledEmailTaskDao.count();
}
more concretey methods go here
如果您想知道
GenericService<E, I>是为我要实现的所有服务指定CRUD方法的接口，这就是EmailTaskService实施它的原因。所以我的问题是，如何通过自动装配或其他明智的方法获得对
EmailTaskService或EmailTaskServiceImpl的成功引用。如果这不可能，为什么？编辑1（上下文配置）：
询问，您将收到：
<beans Spring namespace config etc etc etc>
<context:component-scan base-package="au.com.mail" />
<mvc:annotation-driven />
<tx:annotation-driven />
<task:annotation-driven/>
<!-- Project Properties -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<value>classpath:project.properties</value>
</property>
</bean>
</beans>
编辑2：实际正确的Stacktrace：
[junit] Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scheduledEmailTaskServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected au.com.mail.service.emailtask.EmailTaskService au.com.mail.service.emailtask.ScheduledEmailTaskService.emailTaskService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [au.com.mail.service.emailtask.EmailTaskService] 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), @org.springframework.beans.factory.annotation.Qualifier(value=emailTaskService)}
[junit] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
[junit] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
[junit] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
[junit] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
[junit] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
[junit] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
[junit] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
[junit] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
[junit] at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
[junit] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
[junit] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
[junit] at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:120)
[junit] at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
[junit] at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:100)
[junit] at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:248)
[junit] at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContextInternal(CacheAwareContextLoaderDelegate.java:64)
[junit] at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContext(CacheAwareContextLoaderDelegate.java:91)
[junit] ... 50 more
[junit] Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: protected au.com.mail.service.emailtask.EmailTaskService au.com.mail.service.emailtask.ScheduledEmailTaskService.emailTaskService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [au.com.mail.service.emailtask.EmailTaskService] 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), @org.springframework.beans.factory.annotation.Qualifier(value=emailTaskService)}
[junit] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:517)
[junit] at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
[junit] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:286)
[junit] ... 66 more
[junit] Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [au.com.mail.service.emailtask.EmailTaskService] 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), @org.springframework.beans.factory.annotation.Qualifier(value=emailTaskService)}
[junit] at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:988)
[junit] at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:858)
[junit] at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
[junit] at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:489)
[junit] ... 68 more
在您问之前，是的，我的JUnit已配置为正确使用Spring Application Context。
最佳答案
鉴于您到处都有@Transactional，我将假设您对JDK代理进行了一些代理。
事实证明，JKD代理只能获取目标bean的接口，而不能获取它们的类层次结构。因此，为您的EmailTaskServiceImpl创建的代理不是EmailTaskServiceImpl类型，因此无法填写该类型的注入目标。相反，它的类型是EmailTaskService，但是您的字段是
@Autowired
protected EmailTaskServiceImpl emailTaskService;
这样就不会了。
有两种解决方案：
首先是将您的配置更改为使用CGLIB代理。您需要将事务配置更改为
<tx:annotation-driven proxy-target-class="true" />
并将CGLIB库添加到您的类路径中。
第二是将您的字段更改为
@Autowired
@Qualifier("someName")
protected EmailTaskService emailTaskService;
和你的班级声明
@Service("someName")
public class EmailTaskServiceImpl extends EmailTaskService<EmailTask, Long>{
在确定要注入哪个bean时，Spring将使用名称而不是类型。这是必需的，因为您有许多
EmailTaskService候选bean。