使用@Configuration注解

@Configuration
public class AppConfig {

	@Bean
	public BeanOne beanOne() {
		return new BeanOne(beanTwo());
	}

	@Bean
	public BeanTwo beanTwo() {
		return new BeanTwo();
	}
}

@Configuration
class AppConfig {

	@Bean
	fun beanOne() = BeanOne(beanTwo())

	@Bean
	fun beanTwo() = BeanTwo()
}

public abstract class CommandManager {
	public Object process(Object commandState) {
		// grab a new instance of the appropriate Command interface
		Command command = createCommand();
		// set the state on the (hopefully brand new) Command instance
		command.setState(commandState);
		return command.execute();
	}

	// okay... but where is the implementation of this method?
	protected abstract Command createCommand();
}

abstract class CommandManager {
	fun process(commandState: Any): Any {
		// grab a new instance of the appropriate Command interface
		val command = createCommand()
		// set the state on the (hopefully brand new) Command instance
		command.setState(commandState)
		return command.execute()
	}

	// okay... but where is the implementation of this method?
	protected abstract fun createCommand(): Command
}

@Bean
@Scope("prototype")
public AsyncCommand asyncCommand() {
	AsyncCommand command = new AsyncCommand();
	// inject dependencies here as required
	return command;
}

@Bean
public CommandManager commandManager() {
	// return new anonymous implementation of CommandManager with createCommand()
	// overridden to return a new prototype Command object
	return new CommandManager() {
		protected Command createCommand() {
			return asyncCommand();
		}
	}
}

@Bean
@Scope("prototype")
fun asyncCommand(): AsyncCommand {
	val command = AsyncCommand()
	// inject dependencies here as required
	return command
}

@Bean
fun commandManager(): CommandManager {
	// return new anonymous implementation of CommandManager with createCommand()
	// overridden to return a new prototype Command object
	return object : CommandManager() {
		override fun createCommand(): Command {
			return asyncCommand()
		}
	}
}

@Configuration
public class AppConfig {

	@Bean
	public ClientService clientService1() {
		ClientServiceImpl clientService = new ClientServiceImpl();
		clientService.setClientDao(clientDao());
		return clientService;
	}

	@Bean
	public ClientService clientService2() {
		ClientServiceImpl clientService = new ClientServiceImpl();
		clientService.setClientDao(clientDao());
		return clientService;
	}

	@Bean
	public ClientDao clientDao() {
		return new ClientDaoImpl();
	}
}

@Configuration
class AppConfig {

	@Bean
	fun clientService1(): ClientService {
		return ClientServiceImpl().apply {
			clientDao = clientDao()
		}
	}

	@Bean
	fun clientService2(): ClientService {
		return ClientServiceImpl().apply {
			clientDao = clientDao()
		}
	}

	@Bean
	fun clientDao(): ClientDao {
		return ClientDaoImpl()
	}
}