Question

我想实现前面提到的 JPA 存储库 here。我想我的问题是我想使用 JPA 存储库本身的一些功能，我 @Autorwired 它但我不完全确定

错误信息：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'addBothStudentsHandler': Unsatisfied dependency expressed through method 'setMajorRepository' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'majorRepository' defined in io.asiam.tansiq.repositories.MajorRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Cannot create inner bean '(inner bean)#78f146b5' of type [org.springframework.data.repository.core.support.RepositoryFragmentsFactoryBean] while setting bean property 'repositoryFragments'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#78f146b5': Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customMajorRepositoryImplFragment': Cannot resolve reference to bean 'customMajorRepositoryImpl' while setting constructor argument; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'customMajorRepositoryImpl': Unsatisfied dependency expressed through field 'majorRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'majorRepository': FactoryBean threw exception on object creation; nested exception is java.lang.NullPointerException

到目前为止我尝试过的：

1- 尝试使用 setter-based @Autowired 而不是 field-based（但没有变化）

2- 尝试使用 @Lazy 也没有任何改变

**代码：**

CustomMajorRepository.java

public interface CustomMajorRepository {
    void addStudentToMajor(Student student, Major major);
    void increaseMajorLimit(UUID majorId, int amount);
}

CustomMajorRepositoryImpl.java

    private MajorRepository majorRepository;

    public MajorRepository getMajorRepository() {
        return majorRepository;
    }

    @Autowired
    public void setMajorRepository(MajorRepository majorRepository) {
        this.majorRepository = majorRepository;
    }
// rest of implementation details

MajorRepository.java

@Lazy
public interface MajorRepository extends JpaRepository<Major, UUID>, CustomMajorRepository {
}

Answer 1

我认为你应该通过构造函数或setter使用依赖注入，例如：

private MajorRepository majorRepository;

    public CostumMajorRepositoryImpl(MajorRepository mh) {
        this.majorRepository = mh;
    }

这是关于 setter 和构造函数注入的 spring.io 文章：

https://spring.io/blog/2007/07/11/setter-injection-versus-constructor-injection-and-the-use-of-required/

春天不满足的依赖

1 个答案: