Java学习之错误记录（1）---Caused by: java.lang.IllegalArgumentException: Not a managed type: class java.lang.

学习使用springboot+JPA时候报错如下： 

org.spring work.beans.factory.UnsatisfiedDependencyException: Error creating bean with name \'daoController\': Unsatisfied dependency expressed through field \'userDao\'; nested exception is org.spring work.beans.factory.BeanCreationException: Error creating bean with name \'userDao\': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang. 
	at org.spring work.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:586) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.annotation.Injection data.inject(Injection data.java:90) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1341) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:572) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at org.spring work.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at org.spring work.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at org.spring work.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at org.spring work.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at org.spring work.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]
	at com.java.security.SpringSecurityApplication.main(SpringSecurityApplication.java:17) [classes/:na]
Caused by: org.spring work.beans.factory.BeanCreationException: Error creating bean with name \'userDao\': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang. 
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1699) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:573) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.config.DependencyDe or.resolveCandidate(DependencyDe or.java:251) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	... 19 common  s omitted
Caused by: java.lang.IllegalArgumentException: Not a managed type: class java.lang. 
	at org.hibernate. model.internal. modelImpl.managedType( modelImpl.java:473) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
	at org.spring work.data.jpa.repository.support.Jpa modelEntityInformation.<init>(Jpa modelEntityInformation.java:74) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:66) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:180) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:118) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:101) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:304) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.repository.core.support.RepositoryFactoryBeanSupport.lambda$afterPropertiesSet$4(RepositoryFactoryBeanSupport.java:290) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.util.Lazy.getNullable(Lazy.java:141) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.util.Lazy.get(Lazy.java:63) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:293) ~[spring-data-commons-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:102) ~[spring-data-jpa-2.0.10.RELEASE.jar:2.0.10.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1758) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.spring work.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1695) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	... 29 common  s omitted

经过检查，发现是在UserDao中

public interface UserDao extends JpaRepository{
}没有指明实体类和主键，改成

public interface UserDao extends JpaRepository<User,Integer>{


}

问题解决