数据持久性的 Spring Boot 依赖注入错误

Question

I am new to Spring Boot, but am currently building an application which used Spring not for its web app capabilities, but rather takes advantage of its data source capabilities (using JPA annotations). When running my code, the following compilation error takes place:

21-11-14 18:12:17.765 ERROR 13432 --- [  restartedMain] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'taskSerializableInteractor' defined in file [/Users/myname/softwarename/target/classes/api/TaskSerializableInteractor.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'taskSerializableRepository' defined in api.TaskSerializableRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class api.TaskSerializable

This error suggests to me that Spring Boot is having some issues with handling the dependency injection defined in the application's API classes. The project itself is quite large and I don't know which code is required for debugging here, but I'm happy to post snippets if required. I've Googled for hours and have no clue how to figure this out. Any tips on how I can go about resolving this error?

Answer 1

As the error says, the dependency you want to inject couldn't do it. This may happen when:

1. There is no matching constructor. For example, if you have this class

//BAD PRACTICE
class Foo(){
    @Autowired
    private MyClass1 myClass1;
    @Autowired
    private MyClass2 myClass2;
    @Autowired
    private MyClass3 myClass3;

...
}

And you don't define any constructor, the dependency not being inject. The correct way in this case:

class Foo(){
    private MyClass1 myClass1;
    private MyClass2 myClass2;
    private MyClass3 myClass3;

    @Autowired
    public Foo(MyClass1 myClass1, MyClass2 myClass2, MyClass3 myClass3){
        this.myClass1 = myClass1;
        this.myClass2 = myClass2;
        this.myClass3 = myClass3;
    }
}

2. The dependency you want to inject is no @Component and there is no @Bean defined to inject it. The name of dependency you want to inject and method defined on @Bean should be equals. Continue with previous example:

@Configuration
public class MyBeanConfiguration(){

    @Bean
    public MyClass1 myClass1(){
        return new MyClass1(PARAMETERS)
    }

    ... SO ON ...
}

So that, check if classes/api/TaskSerializableInteractor have correct constructor and there is a configuration of beans defined.

If you could shown part of the class, it's better to have more correct idea.