我正在尝试在Spring应用程序上下文中注册一个普通的Java类。我可以@Autowire
在其他要使用的类中。
普通Java类：
public class MyBean {
public void showMe() {
System.out.println("test me");
}
}
用于在春季上下文中注册课程的代码
public class CustomeBeanCongif implements ApplicationListener<ApplicationEvent> {
@Autowired
GenericApplicationContext ctx;
@Override
public void onApplicationEvent(ApplicationEvent event) {
System.out.println("Starting Config");
BeanDefinition beanDef = new GenericBeanDefinition();
beanDef.setScope(BeanDefinition.SCOPE_SINGLETON);
beanDef.setAutowireCandidate(true);
try {
ctx.registerBean("myxyzBean", MyBeanStandalone.class, new MyBeanStandalone(), beanDef);
}
catch(BeanDefinitionOverrideException e) {
System.out.println("CLassName: " + e.getBeanDefinition().getBeanClassName());
System.out.println(e.getBeanName());
System.out.println(e.getBeanDefinition());
e.printStackTrace();
}
}
}
Driver class
@SpringBootApplication
public class DemoApplication implements CommandLineRunner {
@Autowired
ApplicationContext ctx;
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@Override
public void run(String... args) throws Exception {
MyBean test = ctx.getBean(MyBean.class);
}
}
应用程序抛出错误，说另一个已注册的bean。日志：
2020-03-09 12:10:47.634 INFO 26684 --- [ main] com.example.demo.DemoApplication : No active profile set, falling back to default profiles: default
Starting Config
2020-03-09 12:10:48.740 INFO 26684 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 2.272 seconds (JVM running for 2.812)
Starting Config
CLassName: com.example.demo.config.MyBean
myxyzBean
Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null
org.springframework.beans.factory.support.BeanDefinitionOverrideException: Invalid bean definition with name 'myxyzBean' defined in null: Cannot register bean definition [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] for bean 'myxyzBean': There is already [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] bound.
at org.springframework.beans.factory.support.DefaultListableBeanFactory.registerBeanDefinition(DefaultListableBeanFactory.java:927)
at org.springframework.context.support.GenericApplicationContext.registerBeanDefinition(GenericApplicationContext.java:323)
at org.springframework.beans.factory.support.BeanDefinitionReaderUtils.registerBeanDefinition(BeanDefinitionReaderUtils.java:167)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.doRegisterBean(AnnotatedBeanDefinitionReader.java:285)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.registerBean(AnnotatedBeanDefinitionReader.java:233)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.registerBean(AnnotationConfigApplicationContext.java:188)
at org.springframework.context.support.GenericApplicationContext.registerBean(GenericApplicationContext.java:387)
at com.example.demo.config.CustomeBeanCongif.onApplicationEvent(CustomeBeanCongif.java:33)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360)
at org.springframework.boot.context.event.EventPublishingRunListener.started(EventPublishingRunListener.java:98)
at org.springframework.boot.SpringApplicationRunListeners.started(SpringApplicationRunListeners.java:71)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:321)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
at com.example.demo.DemoApplication.main(DemoApplication.java:22)
2020-03-09 12:10:48.751 INFO 26684 --- [ main] ConditionEvaluationReportLoggingListener :
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
Starting Config
CLassName: com.example.demo.config.MyBean
myxyzBean
Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null
org.springframework.beans.factory.support.BeanDefinitionOverrideException: Invalid bean definition with name 'myxyzBean' defined in null: Cannot register bean definition [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] for bean 'myxyzBean': There is already [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] bound.
at org.springframework.beans.factory.support.DefaultListableBeanFactory.registerBeanDefinition(DefaultListableBeanFactory.java:927)
at org.springframework.context.support.GenericApplicationContext.registerBeanDefinition(GenericApplicationContext.java:323)
at org.springframework.beans.factory.support.BeanDefinitionReaderUtils.registerBeanDefinition(BeanDefinitionReaderUtils.java:167)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.doRegisterBean(AnnotatedBeanDefinitionReader.java:285)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.registerBean(AnnotatedBeanDefinitionReader.java:233)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.registerBean(AnnotationConfigApplicationContext.java:188)
at org.springframework.context.support.GenericApplicationContext.registerBean(GenericApplicationContext.java:387)
at com.example.demo.config.CustomeBeanCongif.onApplicationEvent(CustomeBeanCongif.java:33)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360)
at org.springframework.boot.context.event.EventPublishingRunListener.failed(EventPublishingRunListener.java:112)
at org.springframework.boot.SpringApplicationRunListeners.callFailedListener(SpringApplicationRunListeners.java:90)
at org.springframework.boot.SpringApplicationRunListeners.failed(SpringApplicationRunListeners.java:83)
at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:797)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:325)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
at com.example.demo.DemoApplication.main(DemoApplication.java:22)
2020-03-09 12:10:48.762 ERROR 26684 --- [ main] o.s.boot.SpringApplication : Application run failed
java.lang.IllegalStateException: Failed to execute CommandLineRunner
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:787) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:768) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:322) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
at com.example.demo.DemoApplication.main(DemoApplication.java:22) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myxyzBean': Cannot create inner bean '(inner bean)#662706a7' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#662706a7': Instantiation of bean failed; nested exception is java.lang.IllegalStateException: No bean class specified on bean definition
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:389) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:134) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:705) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:196) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1358) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1204) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:227) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveNamedBean(DefaultListableBeanFactory.java:1155) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveBean(DefaultListableBeanFactory.java:416) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:349) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:342) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1126) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at com.example.demo.DemoApplication.run(DemoApplication.java:47) [classes/:na]
at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:784) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
... 5 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#662706a7': Instantiation of bean failed; nested exception is java.lang.IllegalStateException: No bean class specified on bean definition
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1320) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1214) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:374) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
... 23 common frames omitted
Caused by: java.lang.IllegalStateException: No bean class specified on bean definition
at org.springframework.beans.factory.support.AbstractBeanDefinition.getBeanClass(AbstractBeanDefinition.java:423) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:68) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1312) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
... 27 common frames omitted
Starting Config
CLassName: com.example.demo.config.MyBean
myxyzBean
Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null
org.springframework.beans.factory.support.BeanDefinitionOverrideException: Invalid bean definition with name 'myxyzBean' defined in null: Cannot register bean definition [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] for bean 'myxyzBean': There is already [Generic bean: class [com.example.demo.config.MyBean]; scope=singleton; abstract=false; lazyInit=null; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] bound.
at org.springframework.beans.factory.support.DefaultListableBeanFactory.registerBeanDefinition(DefaultListableBeanFactory.java:927)
at org.springframework.context.support.GenericApplicationContext.registerBeanDefinition(GenericApplicationContext.java:323)
at org.springframework.beans.factory.support.BeanDefinitionReaderUtils.registerBeanDefinition(BeanDefinitionReaderUtils.java:167)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.doRegisterBean(AnnotatedBeanDefinitionReader.java:285)
at org.springframework.context.annotation.AnnotatedBeanDefinitionReader.registerBean(AnnotatedBeanDefinitionReader.java:233)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.registerBean(AnnotationConfigApplicationContext.java:188)
at org.springframework.context.support.GenericApplicationContext.registerBean(GenericApplicationContext.java:387)
at com.example.demo.config.CustomeBeanCongif.onApplicationEvent(CustomeBeanCongif.java:33)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403)
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360)
at org.springframework.context.support.AbstractApplicationContext.doClose(AbstractApplicationContext.java:1012)
at org.springframework.context.support.AbstractApplicationContext.close(AbstractApplicationContext.java:978)
at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:803)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:325)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
at com.example.demo.DemoApplication.main(DemoApplication.java:22)
MyBean类由第三方jar提供，因此我无法对此进行更改。感谢您的帮助。
删除CustomeBeanCongif，然后将@Bean方法添加到@SpringBootApplication或自定义@Configuration类中。
@Bean
public MyBean myBean() {
return new MyBean();
}
并且仅此而已是您注册bean所需要的。