问题

org.springframework.context.support.AbstractApplicationContext refresh警告: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name \'user\': Unsatisfied dependency expressed through field \'cat\'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type \'com.wei.pojo.Cat\' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name \'user\': Unsatisfied dependency expressed through field \'cat\'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type \'com.wei.pojo.Cat\' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:226)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:893)at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:144)at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:85)at com.wei.pojo.UserTest.fun1(UserTest.java:22)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.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)at org.junit.runners.ParentRunner.run(ParentRunner.java:309)at org.junit.runner.JUnitCore.run(JUnitCore.java:160)at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type \'com.wei.pojo.Cat\' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1714)at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1270)at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1224)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)... 37 moreProcess finished with exit code -1

原因

user依赖了cat，而cat没有加上组件注解@component

解决

@Componentpublic class Cat {public void shot(){System.out.println(\"cat shot!!!\");}}

总结

当没有注入时应该干嘛？
1.检查是否有扫描包？xml配置和注解配置二选一。

xml配置 ClassPathXmlApplicationContext

<context:component-scan base-package=\"com.wei\" />

测试类

@Testpublic void fun1(){ApplicationContext applicationContext = new ClassPathXmlApplicationContext(\"applicationContext.xml\");User bean = applicationContext.getBean(User.class);Cat cat = bean.getCat();cat.shot();}

注解配置 AnnotationConfigApplicationContext

@Configuration@ComponentScan(\"com.wei\")public class ApplicationConfig {}

//测试类@Testpublic void fun2(){ApplicationContext applicationContext = new AnnotationConfigApplicationContext(ApplicationConfig.class);User bean = applicationContext.getBean(User.class);Cat cat = bean.getCat();cat.shot();}

2.检查@autowire 的依赖类上是否有@component 等。