java - Main 中的内部 CrudRepository 接口(interface)不起作用

Question

我正在使用 spring-data-jpa 进行一些测试，因此为了不创建新文件来执行存储库接口(interface)，我将其放在 Main 中，如下所示:

@SpringBootApplication
public class Application {

private static final Logger log = LoggerFactory.getLogger(Application.class);

public static void main(String[] args) {
    SpringApplication.run(Application.class);
}


@Bean
public CommandLineRunner demo(BRepository repository) {
    return (args) -> {
        log.info("Insert a");
        repository.save(new EntityA("TestA"));

        log.info("Find a " + repository.findOne(1));

    };
}


@Entity
@Table(name = "A")
public static class EntityA{

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;

    @Column(name = "NAME")
    private String name;

    //Getters, setters && constructors

}

public interface BRepository extends CrudRepository<EntityA, Integer> {

}

}

然后我用 @Bean CommandLineRunner 对其进行了测试以查看输出，但我得到了 UnsatisfiedDependencyException:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demo' defined in hello.Application: Unsatisfied dependency expressed through method 'demo' parameter 0: No qualifying bean of type [hello.Application$BRepository] found for dependency [hello.Application$BRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [hello.Application$BRepository] found for dependency [hello.Application$BRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1123) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1018) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:776) ~[spring-beans-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.3.2.RELEASE.jar:4.3.2.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:313) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174) [spring-boot-1.4.0.RELEASE.jar:1.4.0.RELEASE]
    at hello.Application.main(Application.java:27) [classes/:na] 

最后，为了确保我没有做错什么，我在新文件中测试了接口(interface)存储库并且它可以工作。

• 有人知道为什么存储库不能使用内部接口(interface)吗？

• 这是一个问题还是由于某种原因不起作用？ (或者也许我做错了什么)

Answer 1

Spring 看不到嵌套存储库，要让它看到，请使用 @EnableJpaRepositories (尽管它已经包含在 @SpringBootApplication 中)并设置 considerNestedRepositories boolean 值到 true。

来源帖子:https://stackoverflow.com/a/24485491/2816631