如何将Springbean（custructor）注入到Mapstruct的抽象映射器中？

Question

我有下面的映射器类，我想在其中使用CounterService。我正在尝试构造函数注入，但不起作用，并且null正在打印。

@Mapper(componentModel = "spring", uses = CounterService.class, injectionStrategy = InjectionStrategy.CONSTRUCTOR)
public abstract class CarMapper {

    private CounterService counterService;

    public CarMapper(CounterService counterService) {
       this.counterService = counterService;
    }

    public abstract Car dtoToEntity(CarDto carDto);

    public CarDto entityToDto(Car car) {
        System.out.println(counterService)
        //....
        return carDto;
    }

}

mapStruct实现类

@Component
public class CarMapperImpl extends CarMapper{

  @Override
  public Car dtoToEntity(CarDto carDto){
    //...
  }
}

如果我使用@AutoWired使用字段注入，这样它就可以正常工作。这意味着Spring不支持抽象类的构造函数注入。是因为抽象类不能直接实例化，需要子类来实例化吗？
有没有什么方法mapSTRt可以在实现类中创建一个构造函数，如下所示：

  public CarMapperImpl(CounterService counterService){
    super(counterService);
  }

这样，构造函数注入应该可以工作。

Answer 1

您还可以使用如下所示的映射器装饰器。此外，始终确保检查生成的类。

@DecoratedWith(CarDecoratorMapper.class)
@Mapper(componentModel = "spring")
public interface CarMapper {

    Car dtoToEntity(CarDto carDto);
    CarDto entityToDto(Car car);

}

public abstract class CarDecoratorMapper implements CarMapper {

    @Autowired
    private CarMapper delegate;

    @Autowired
    private CounterService counterService;    

    public Car dtoToEntity(CarDto carDto) {
        Car car = delegate.dtoToEntity(carDto);
        car.setProperty(counterService.count(carDto));
    
        return car;
    }

    public CarDto entityToDto(Car car) {
        CarDto carDto = delegate.entityToDto(car);
        carDto.setProperty(counterService.countDto(car));

        return carDto;
    }
}

Answer 2

这与Spring无关。MapStruct团队慎重决定不使用超级构造函数。

不过，您可以使用setter注入。

@Mapper(componentModel = "spring", uses = CounterService.class, injectionStrategy = InjectionStrategy.CONSTRUCTOR)
public abstract class CarMapper {

    private CounterService counterService;

    public abstract Car dtoToEntity(CarDto carDto);

    public CarDto entityToDto(Car car) {
        System.out.println(counterService)
        //....
        return carDto;
    }

    @Autowired
    public void setCounterService(CounterService counterService) {
        this.counterService = counterService;
    }

}