java - NoSuchBeanDefinition 异常

Question

这个问题已经有答案了:

What is a NoSuchBeanDefinitionException and how do I fix it? (1 个回答)

已关闭 5 年前。

在尝试运行我的 Spring Boot 应用程序时，出现以下错误:没有此类 bean 定义异常。请让我知道我错过了什么。它是一个简单的 spring 框架，但我遇到了这个错误。如有任何帮助，我们将不胜感激。

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.cnanational.servicecommon.validation.Validator<com.cnanational.productservice.model.DealerSeriesAttributesRequest>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1493)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835)

下面给出的是调用 bean 的服务类

@Service
public class ProductServiceImpl implements ProductService {

    private final Logger log = LoggerFactory.getLogger(getClass());

    private final Validator<SeriesSurchargesRequest> seriesSurchargesRequestValidator;

    private final Validator<DealerSeriesAttributesRequest> dealerSeriesAttributesRequestValidator;

    private final ProductServiceDao productDao;

    @Value("${spring.application.name}")
    private String serviceName;

    @Autowired
    public ProductServiceImpl(
            final ProductServiceDao productDao, final Validator<SeriesSurchargesRequest> seriesSurchargesRequestValidator,
            final Validator<DealerSeriesAttributesRequest> dealerSeriesAttributesRequestValidator )
    {
        this.productDao = productDao;
        this.seriesSurchargesRequestValidator = seriesSurchargesRequestValidator;
        this.dealerSeriesAttributesRequestValidator = dealerSeriesAttributesRequestValidator;
    }

    @Override
    public SeriesSurcharges getSurcharges(SeriesSurchargesRequest stdOptions) {

    this.seriesSurchargesRequestValidator.validateAndThrowIfInvalid(
                stdOptions,
                "SeriesSurchargesRequest");

        SeriesSurcharges charges = productDao.findSurcharges(stdOptions);

        return charges;
    }

    @Override
    public List<DealerSeriesAttribute> getDealerSeriesAttributes(DealerSeriesAttributesRequest request) throws Exception {         
           this.dealerSeriesAttributesRequestValidator.validateAndThrowIfInvalid(
                request,
                "dealerSeriesAttributesRequest");
           
           List <DealerSeriesAttribute> result = new ArrayList<DealerSeriesAttribute>();
           
           for (ProductSeriesFilter psfilter : request.getProductSeriesFilters()) {
                log.debug("getDealerSeriesAttributes-1: ProductSeriesFilter: " + psfilter.toString());
                List<DealerSeriesAttribute> dsa = productDao.getDealerSeriesAttributes( request);
                result.addAll(dsa);
                log.debug("Product service Impl : The size of dsa, sizes={}", dsa.size());
           }           
           return new ArrayList<DealerSeriesAttribute>(result);         
    }
}

下面给出的是 Validator 类。

public class CreateDealerSeriesAttributesRequestValidator implements Validator<DealerSeriesAttributesRequest>{

    private final SmartValidator smartValidator;

    public CreateDealerSeriesAttributesRequestValidator(final SmartValidator smartValidator)
    {
        this.smartValidator = smartValidator;
    }

    @Override
    public boolean supports(Class<?> clazz) {
        return DealerSeriesAttributesRequest.class.equals(clazz);
    }

    @Override
    public void validate(Object target, Errors errors) {}

    @Override
    public SmartValidator smartValidator() {
        return smartValidator;
    }
}

Answer 1

我猜你的包 com.cnanational.productservice.model 不在你的入口点所在的包下(用 @SpringBootApplication 注释的类)

Spring需要知道去哪里扫描bean，在spring boot中，默认情况下spring boot会扫描@SpringBootApplication注解的类所在的包以及该包下的包，也可以使用@componantscan指定包您需要扫描，这样您就可以像这样解决您的问题

@SpringBootApplication
@ComponentScan("com.cnanational.productservice.model")

或者将您的 bean 实现放在默认情况下会扫描的包下。

此外，您还需要确保您的类已注册为 bean，因此如果您的 Validator 接口(interface)未注册为 bean，您可以注释 Validator 或 CreateDealerSeriesAttributesRequestValidator @Component 或使用 @Bean 在以下之一下创建 CreateDealerSeriesAttributesRequestValidator 的实例您的配置类。

注意由于您使用的是 Autowiring 接口(interface)，因此当您有多个实现时需要小心，您需要使用 @Qualifier 帮助 spring 决定选择哪个实现