受弹簧数据的启发，我想创建一个抽象的RESTController，可以将其扩展到很多控制器上。我创建了以下类：

@Controller

public abstract class RESTController>

{

@Autowired

private R repository;

@RequestMapping(method=RequestMethod.GET, params={"id"})

@ResponseBody

public E getEntity(@RequestParam PK id)

{

return repository.findOne(id);

}

...

}

我希望泛型将允许我在存储库中使用@Autowired，但出现以下错误：

SEVERE: Allocate exception for servlet appServlet

org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [org.springframework.data.repository.PagingAndSortingRepository] is defined: expected single matching bean but found 3: [groupRepository, externalCourseRepository, managedCourseRepository]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:800)

at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)

at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)

我知道错误告诉我，@ Autowired有多个匹配项。我很困惑，因为我认为通过创建以下控制器它会起作用：

@Controller

@RequestMapping(value="/managedCourse")

public class ManagedCourseController extends RESTController

{

...

}

通过在RESTController中使用如下方法可以轻松解决此问题：

protected abstract R getRepository();

然后在实现类中执行此操作：

@Autowired

private ManagedCourseRepository repository;

@Override

protected ManagedCourseRepository getRepository()

{

return repository;

}

我只是想知道是否有人对我如何使它起作用有任何想法。

我也发现了这个有趣的伯爵。