源为空MapStruct时另一个bean属性的缺省值

@Mapper
public interface MyMapper {

    MyMapper INSTANCE = Mappers.getMapper(MyMapper.class);

    @Mapping(target = "destinationProperty", defaultValue = "default value")
    DestinationBean map(SourceBean sourceBean);

    @Mapping(target = "destinationProperty", defaultValue = "default value")
    void updateDestinationBean(SourceBean sourceBean, @MappingTarget DestinationBean destinationBean);
}

SourceBean source = new SourceBean();
source.setSourceProperty(null); // 将源对象的属性设置为空

DestinationBean destination = MyMapper.INSTANCE.map(source);
System.out.println(destination.getDestinationProperty()); // 输出：default value

// 或者使用updateDestinationBean方法更新已存在的目标对象
DestinationBean existingDestination = new DestinationBean();
existingDestination.setDestinationProperty("existing value");

MyMapper.INSTANCE.updateDestinationBean(source, existingDestination);
System.out.println(existingDestination.getDestinationProperty()); // 输出：default value