出现org.springframework.beans.factory.NoSuchBeanDefinitionException 的解决思路

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private cn.itcast.crm.service.BaseDictService cn.itcast.crm.controller.CustomerController.baseDictService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [cn.itcast.crm.service.BaseDictService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}


严重: StandardWrapper.Throwable
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customerController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private cn.itcast.crm.service.BaseDictService cn.itcast.crm.controller.CustomerController.baseDictService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [cn.itcast.crm.service.BaseDictService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

 解决问题的思路：

1.如果您使用注释进行配置，则可能会缺少cn.itcast.crm.service.BaseDictService实现的注释（@Service或@Component）。

2.如果您使用（仅）xml，您可能会错过BaseDictService实现的<bean>定义。 

3.如果您使用注释并且实现注释正确，请检查扫描实现所在的包

（检查各自组件的自动扫描组件<context：component-scan base-package = “XXXX”）

或者（Spring自动扫描<context:annotation-config/>）

4.代码有无错误：例子如下,Service类实现接口具有相同申明方法的Mapper接口，都会导致Spring无法识别相应的bean：

public interface BaseDictMapper {
     //根据类别代码查询数据
      List<BaseDict> queryBaseDictByDictTypeCode(String dictTypeCode);

}

public interface BaseDictService {
      //根据类别代码查询
      List<BaseDict> queryBaseDictByDictTypeCode(String dictTypeCode);
}

public class BaseDictServiceImpl implements BaseDictMapper {    //错误：应该实现为BaseDictService
      @Autowired
      private BaseDictMapper baseDictMapper;
      @Override
      public List<BaseDict> queryBaseDictByDictTypeCode(String  dictTypeCode)  {
            List<BaseDict> list =  this.baseDictMapper.queryBaseDictByDictTypeCode(dictTypeCode);
            return list;
      }
}