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等）。

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,

BaseDictMapper在mapper文件下并在相关的mapper.xml进行相关配置，BaseDictService在service文件下并做了相关的spring配置文件做了对应的配置。Service实现具有相同申明方法的mapper接口（而spring并不能扫描到mapper文件夹下的接口和类），因此BeanFactory在Spring Context中没有找到bean的实例，最终导致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;
      }
}

5.是否确实与注入相关便签的依赖。比如dubbo服务下，添加了spring的相关依赖但是服务端并不需要Spring的@Service标签，而是dubbo的@Service标签。检查maven依赖是否正确，修改完毕记得Install，report下

简单代码：

pom.xml

<dependencies>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jms</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
        </dependency>
        <!-- dubbo相关 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.sgroschupf</groupId>
            <artifactId>zkclient</artifactId>
        </dependency>
        ...
    </dependencies>

service:

import com.alibaba.dubbo.config.annotation.Service;
import com.chunxiansheng.mapper.TbBrandMapper;
import com.chunxiansheng.pojo.TbBrand;
import com.chunxiansheng.service.BrandService;
import org.springframework.beans.factory.annotation.Autowired;
 
import java.util.List;
 
@Service
public class BrandServiceImpl implements BrandService {
 
    @Autowired
    private TbBrandMapper brandMapper;
    ...
}

6.检查数据源，JDBC等有没有配置错误。

例如具体查看mapper，dao下的spring配置文件和db.properties的配置。

7.推荐使用SpringBoot，可以减少很多配置的操作，适合开发。