先看如下两个注入到spring容器中的bean， 一个是 UserNewManager， 一个是 UserManager。
@Service public class UserNewManager { public void doSomething() { } } @Service public class UserManager { ... }
再看下面的testcase，利用@Resource注解来注入bean。
@SpringBootTest @RunWith(SpringRunner.class) public class ResourceTest { @Resource private UserNewManager userManager; @Test public void test() { userManager.doSomething(); } }
在运行test方法时，会抛异常：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'springtrans.resourcetest.ResourceTest': Injection of resource dependencies failed;
nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException:
Bean named 'userManager' is expected to be of type 'springtrans.resourcetest.UserNewManager' but was
actually of type 'springtrans.resourcetest.UserManager'
原因：@Resource注解有两个重要的属性：name和type。在一个使用@Resource来注入bean的声明语句中，@Resource优先是按name来解析bean的，当无法解析到bean时会再按照声明type来解析bean，解析完成后注入到对象上。在此testcase案例中，@Resource先按照“userManager”定位到了UserManager这个type，而这个UserManager与实际期望的类型 UserNewManager 产生冲突。就报这个 BeanNotOfRequiredTypeException 异常。 另一种情况，假如容器里没有UserManager这个bean的话，@Resource按照“userManager”就无法解析到type，它会继续按照声明的UserNewManager这个type来解析bean。
我们的项目分为三层，service层→manager层→mapper层，上层依赖下层，相同层级之间一般不相互依赖。其中manager层有一个DataCacheManager，用来做数据缓存。我在一次代码重构中，为了规避未来可能产生的循环引用，我将 DataCacheManager依赖的其他manager改为依赖对应mapper。 例如：我将 @Resource private WorkTypeManager workTypeManager; 改为了 @Resource private WorkTypeMapper workTypeManager; 。结果，在启动springboot服务时，就出现了这个 BeanNotOfRequiredTypeException：Bean named 'workTypeManager' is expected to be of type 'com.xxx.mapper.WorkTypeMapper'but was actually of type 'com.xxx.manager.workTypeManager$$EnhancerBySpringCGLIB$$30dd8c09'。 详细堆栈如下：
2023-08-03 22:30:48.588 [TID:N/A] [] [main] INFO o.a.d.s.b.c.e.AwaitingNonWebApplicationListener:162 - [Dubbo] Current Spring Boot Application is about to shutdown... 2023-08-03 22:30:48.619 [TID:N/A] [] [main] ERROR org.springframework.boot.SpringApplication:858 - Application run failedorg.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'taskApplyDesignImportUserService': Unsatisfied dependency expressed through field'taskApplyManager'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'taskApplyManager': Unsatisfied dependency expressed through field 'dataCacheManager'; nested exception is org.springframework.beans.factory.BeanCreationException:Error creating bean with name 'dataCacheManager': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'workTypeServiceManager' is expected to be of type 'com.xxx.mapper.WorkTypeMapper'but was actually of type 'com.xxx.manager.WorkTypeServiceManager$$EnhancerBySpringCGLIB$$30dd8c09' at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1395) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:849) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) at com.xxx.ServerApplication.main(ServerApplication.java:41) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48) at org.springframework.boot.loader.Launcher.launch(Launcher.java:87) at org.springframework.boot.loader.Launcher.launch(Launcher.java:50) at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:51) Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'taskApplyManager': Unsatisfied dependencyexpressed through field 'dataCacheManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataCacheManager': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException:Bean named 'workTypeServiceManager' is expected to be of type 'com.xxx.mapper.WorkTypeMapper' but was actually of type 'com.xxx.manager.WorkTypeServiceManager$$EnhancerBySpringCGLIB$$30dd8c09' at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1395) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1247) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1167) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593) ... 27 common frames omitted Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataCacheManager': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'workTypeServiceManager' is expected to be of type 'com.xxx.mapper.WorkTypeMapper' but was actually of type 'com.xxx.manager.WorkTypeServiceManager$$EnhancerBySpringCGLIB$$30dd8c09' at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:324) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1395) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1247) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1167) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593) ... 40 common frames omitted Caused by: org.springframework.beans.factory.BeanNotOfRequiredTypeException: Bean named 'workTypeServiceManager' is expected to be of type 'com.xxx.mapper.WorkTypeMapper' but was actually of type 'com.xxx.manager.WorkTypeServiceManager$$EnhancerBySpringCGLIB$$30dd8c09' at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:392) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeanByName(AbstractAutowireCapableBeanFactory.java:452) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:526) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:496) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:636) at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:180) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:321) ... 51 common frames omitted
是为记。
- 39 type actually expected 错误39 type actually expected expected错误token 39 39 argument warning expects 39 clicklocation unrecognized expecting 39 property java type type 39 implicitly expression 39 type unsupported typeerror 39 multipartencoder content-type multipart linkqueue 39 link type domrectreadonly 39 type declarations