Micronaut 定义 Beans

public interface Engine { // (1)
    int getCylinders();
    String start();
}

@Singleton// (2)
public class V8Engine implements Engine {
    private int cylinders = 8;

    @Override
    public String start() {
        return "Starting V8";
    }

    @Override
    public int getCylinders() {
        return cylinders;
    }

    public void setCylinders(int cylinders) {
        this.cylinders = cylinders;
    }
}

@Singleton
public class Vehicle {
    private final Engine engine;

    public Vehicle(Engine engine) {// (3)
        this.engine = engine;
    }

    public String start() {
        return engine.start();
    }
}

interface Engine { // (1)
    int getCylinders()
    String start()
}

@Singleton // (2)
class V8Engine implements Engine {
    int cylinders = 8

    @Override
    String start() {
        "Starting V8"
    }
}

@Singleton
class Vehicle {
    final Engine engine

    Vehicle(Engine engine) { // (3)
        this.engine = engine
    }

    String start() {
        engine.start()
    }
}

interface Engine {
    // (1)
    val cylinders: Int

    fun start(): String
}

@Singleton// (2)
class V8Engine : Engine {

    override var cylinders = 8

    override fun start(): String {
        return "Starting V8"
    }
}

@Singleton
class Vehicle(private val engine: Engine) { // (3)
    fun start(): String {
        return engine.start()
    }
}

final BeanContext context = BeanContext.run();
Vehicle vehicle = context.getBean(Vehicle.class);
System.out.println(vehicle.start());

def context = BeanContext.run()
Vehicle vehicle = context.getBean(Vehicle)
println vehicle.start()

val context = BeanContext.run()
val vehicle = context.getBean(Vehicle::class.java)
println(vehicle.start())