将服务作为参数传递是不好的做法吗？

Question

Suppose I want to use a service in a POJO class, like an implementation of some sort, can I just pass this service as a parameter to this POJO? Or would that be bad practice?

@Service
public class MyService {

    // Inject AnotherService in this service
    public MyService(AnotherService anotherService) {
        // Now pass that service in a POJO
        SomeImplementation impl = new SomeImplementation(anotherService);       
    }
}
 
public class SomeImplementation {

    public SomeImplementation(AnotherService anotherService) {
        // start using the AnotherService here...
    }
}

For this example I used Java and Spring, but this question applies to all languages with dependency injection.

Answer 1

I would say that it's just not making use of the framework you're operating within. That's exactly what DI is for: letting the container handle the components and their relations (eg. if you inject sth multiple times, DI helps you avoid multiple instantiations).

Now, in your case, you can use the @Configurable annotation, which adds a POJO component to the Spring context, and so lets you inject stuff into it.