Spring Boot:如何声明自定义存储库工厂bean

Question

我在应用程序上使用Spring Boot(1.3.3)和基于注释的/ JavaConfig配置.我有以下存储库接口:

@RepositoryRestResource(collectionResourceRel = "something", path = "something")
public interface SomethingRepository 
    extends CrudRepository<SomethingRepository, Long> {

}

我想要做的是覆盖生成的存储库代理中的某些方法的行为.我发现这样做是基于什么文档建议添加新的自定义方法的唯一方法(参见:添加自定义行为,单库),所以我定义如下界面:

public interface SomethingRepositoryCustom {
    Something findOne(Long id);
}

...并添加相应的实现:

public SomethingRepositoryImpl extends SimpleJpaRepository<Something, Long> 
    implements SomethingRepositoryCustom {

    public SomethingRepositoryImpl(<Something> domainClass, EntityManager em) {
        super(domainClass, em);
        this.entityManager = em;
    }

    @Override
    public Something findOne(Long id) {
        System.out.println("custom find one");
        // do whatever I want and then fetch the object
        return null;
    }

}

现在,如果我启动应用程序,我会收到以下错误:

... org.springframework.beans.BeanInstantiationException:无法实例[com.dummy.repositories.SomethingRepositoryImpl]:没有发现默认的构造函数; 嵌套的例外是java.lang.NoSuchMethodException:com.dummy.repositories.SomethingRepositoryImpl()...

问题: 如何解决BeanInstantiationException？我假设我需要声明一个存储库工厂bean,但我不知道如何覆盖Spring Boot配置.

Answer 1

实际上,您必须在@EnableJpaRepositories注释中声明一个新的FactoryBean :

@Configuration
@EnableJpaRepositories(value = "your_package",
        repositoryFactoryBeanClass = CustomFactoryBean.class)
public class ConfigurationClass{}

CustomFactoryBean.java:

public class CustomFactoryBean<R extends JpaRepository<T, I>, T, I extends Serializable> extends JpaRepositoryFactoryBean<R, T, I>{

    @Override
    protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
        return new SimpleJpaExecutorFactory(entityManager);
    }

    /**
     * Simple jpa executor factory
     * @param <T>
     * @param <I>
     */
    private static class SimpleJpaExecutorFactory<T, I extends Serializable> extends JpaRepositoryFactory{

        private EntityManager entityManager;

        /**
         * Simple jpa executor factory constructor
         * @param entityManager entity manager
         */
        public SimpleJpaExecutorFactory(EntityManager entityManager) {
            super(entityManager);
            this.entityManager = entityManager;
        }

        @Override
        protected Object getTargetRepository(RepositoryMetadata metadata) {
            JpaEntityInformation entityInformation =
                    getEntityInformation(metadata.getDomainType());
            return new SomethingRepositoryImpl<T,I>(entityInformation, entityManager);
        }

        @Override
        protected Class getRepositoryBaseClass(RepositoryMetadata metadata) {
            return SomethingRepositoryImpl.class;
        }
    }
}

然后它将是你的SimpleJpaRepository实例:SimpleJpaRepositoryImpl将被使用