Spring Boot无法找到Mapper Bean问题求助

问题代码与错误信息 #

Mapper接口定义 #

@Mapper
@Component
public interface PriceEntityMapper {

    @Mapping(source="brandId", target="brandId")
    @Mapping(source="startDate", target="startDate", qualifiedByName = "timestampToLocalDateTime")
    @Mapping(source="endDate", target="endDate", qualifiedByName = "timestampToLocalDateTime")
    @Mapping(source="priceList", target="priceList")
    @Mapping(source="productId", target="productId")
    @Mapping(source="priority", target="priority")
    @Mapping(source="price", target="price")
    @Mapping(source="curr", target="currency")
    Price priceEntityToPrice(PriceEntity priceEntity);

    @Named("timestampToLocalDateTime")
    default LocalDateTime timestampToLocalDateTime(Timestamp timestamp) {
        return timestamp.toLocalDateTime();
    }
}

Service实现类 #

@Service
public class PriceServiceImpl implements PriceService {

    private final PriceRepository priceRepository;
    private final PriceEntityMapper priceEntityMapper;

    @Autowired
    public PriceServiceImpl(PriceRepository priceRepository, PriceEntityMapper priceEntityMapper) {
        this.priceRepository = priceRepository;
        this.priceEntityMapper = priceEntityMapper;
    }

    @Override
    public Price getPrice(LocalDateTime applicationDate, Integer productId, Integer brandId) {
        try {
            //PriceEntity priceEntity = priceRepository.findByBrandIdAndProductIdAndStartDateLessThanEqualApplicationDateAndEndDateGreaterThanEqualApplicationDate(brandId, productId, Timestamp.valueOf(applicationDate));
            return priceEntityMapper.priceEntityToPrice(new PriceEntity());
        } catch (Exception e) {
            throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Price not found", e);
        }
    }
}

启动错误 #

Parameter 1 of constructor in com.dharian.application.service.PriceServiceImpl required a bean of type 'com.dharian.infraestructure.mapper.PriceEntityMapper' that could not be found.

已做尝试 #

• 为Mapper添加了@Mapper和@Component注解
• 配置了@ComponentScan扫描com.dharian.infraestructure和com.dharian.application包
• 调整过@ComponentScan范围、修改注入方式、调整Mapper注解，但问题未解决

问题原因与解决方案 #

核心原因 #

只给Mapper接口加@Mapper和@Component无法让Spring识别对应的Bean，因为MapStruct默认不会生成Spring管理的实现类，需要显式指定组件模型为Spring。

修正步骤 #

1. 修改@Mapper注解，添加componentModel = "spring"属性，同时可以去掉@Component（因为该属性会自动让生成的实现类带有@Component注解，重复添加可能引发冲突）：

@Mapper(componentModel = "spring")
public interface PriceEntityMapper {
    // 原有代码保持不变
}

2. 确保MapStruct的依赖与注解处理器配置正确：

   • Maven示例（pom.xml）：

     <dependencies>
         <dependency>
             <groupId>org.mapstruct</groupId>
             <artifactId>mapstruct</artifactId>
             <version>1.5.5.Final</version> <!-- 使用最新稳定版 -->
         </dependency>
     </dependencies>
     
     <build>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.1</version>
                 <configuration>
                     <source>17</source> <!-- 对应你的JDK版本 -->
                     <target>17</target>
                     <annotationProcessorPaths>
                         <path>
                             <groupId>org.mapstruct</groupId>
                             <artifactId>mapstruct-processor</artifactId>
                             <version>1.5.5.Final</version>
                         </path>
                     </annotationProcessorPaths>
                 </configuration>
             </plugin>
         </plugins>
     </build>
     

3. 重新编译项目，确保MapStruct生成了正确的Mapper实现类（一般在target/generated-sources/annotations目录下）。

额外注意事项 #

• 确认@ComponentScan的范围确实覆盖了Mapper所在的com.dharian.infraestructure.mapper包，你的现有配置已经包含com.dharian.infraestructure，所以无需调整。
• 不要手动实现Mapper接口，MapStruct会自动生成实现类，手动实现会导致Spring无法注入正确的实例。

内容的提问来源于stack exchange，提问作者Dharian