Hands-On Microservices with Kotlin

Constructor injection

In this book, we have used @Autowired in our examples to illustrate how we ask Spring to inject a bean into our application.

Consider this example of two services and a controller that uses them:

import org.springframework.beans.factory.annotation.Autowiredimport org.springframework.stereotype.Serviceimport org.springframework.web.bind.annotation.*@Serviceclass AccountService {  fun getAccountsByCustomer(customerId: Int): List<Account>      = listOf(Account(1, 125F), Account(2, 500F))}@Serviceclass CustomerService {  @Autowired  private lateinit var accountService: AccountService  fun getCustomer(id: Int): Customer {    val accounts = accountService.getAccountsByCustomer(id)    return Customer(id, "customer$id", accounts)  }}@RestController ...