在科特林自动接线

Question

i've asked this before but never had any answer that made sense.

if ServiceClass is annotated with @Service in java spring i can do

@Autowired
private ServiceClass serviceClass;

or better yet

private final ServiceClass serviceClass;

public userManagementClass(ServiceClass serviceClass) {
        this.serviceClass = serviceClass;
    }

Then i changed to kotlin and..

@Autowired
private lateinit var addressRepository: AddressRepository

where AddressRepository is annotated with @Repository is okey but now the first one, ServiceClass with @Service

@Autowired
private lateinit var serviceClass: ServiceClass

and

@Autowired constructor(
      private val serviceClass: ServiceClass
)

both give error No beans of type found Do i now need a constructor for my services in kotlin or what?

I've read many articles titled like "understanding kotlin lateinit" and what not, but i think im still missing some core ideas since none of them make any goddamn sense... Kotlin documentation is okey, but only for concepts you already know.. otherwise it also is very confusing.

EDIT appears that giving ServiceClass a constructor didnt do anything either

Answer 1

In kotlin (and in Java I think) you can inject your dependencies in the constructor like this:

import org.springframework.stereotype.Repository
import org.springframework.stereotype.Service

@Service
class ServiceClass constructor(
    private val repository: AddressRepository
) {
    // Do stuff here
}

@Repository
class AddressRepository

this is the same that:

@Service
class ServiceClass {
    @Autowired
    private lateinit var repository: AddressRepository

    // Do stuff here
}

@Repository
class AddressRepository

but it allow you to make unit tests without the need of a Spring Context (@SpringBootTest).

Then you can inject your service in another the same way

@Service
class OtherService constructor(
    private val service: ServiceClass
) {
    // Other stuff here
}

There's no bean problem with this code for me. (IntelliJ 2019.1.1)