关于springboot +dataJpa 启动报错的 问题记录

关键错误：nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object

详细错误：org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'documentationPluginsBootstrapper' defined in URL [jar:file:/D:/repository/io/springfox/springfox-spring-web/2.2.2/springfox-spring-web-2.2.2.jar!/springfox/documentation/spring/web/plugins/DocumentationPluginsBootstrapper.class]: Unsatisfied dependency expressed through constructor parameter 1: Error creating bean with name 'webMvcRequestHandlerProvider' defined in URL [jar:file:/D:/repository/io/springfox/springfox-spring-web/2.2.2/springfox-spring-web-2.2.2.jar!/springfox/documentation/spring/web/plugins/WebMvcRequestHandlerProvider.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping]: Factory method 'requestMappingHandlerMapping' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.format.support.FormattingConversionService]: Factory method 'mvcConversionService' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping]: Factory method 'requestMappingHandlerMapping' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.format.support.FormattingConversionService]: Factory method 'mvcConversionService' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'webMvcRequestHandlerProvider' defined in URL [jar:file:/D:/repository/io/springfox/springfox-spring-web/2.2.2/springfox-spring-web-2.2.2.jar!/springfox/documentation/spring/web/plugins/WebMvcRequestHandlerProvider.class]: Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping]: Factory method 'requestMappingHandlerMapping' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.format.support.FormattingConversionService]: Factory method 'mvcConversionService' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerMapping' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping]: Factory method 'requestMappingHandlerMapping' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcConversionService' defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$EnableWebMvcConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.format.support.FormattingConversionService]: Factory method 'mvcConversionService' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.lang.Object

今天在试验springboot 整和datajpa时 出现了这个问题，排查了一遍 发现在实体写成这样public interface UserRepository extends JpaRepository 

这样直接写代码编译是没有问题的 但是实际运行的时候就会出现上面的错误。  

点开JpaRepository 的源码发现JpaRepository 它是继承自PagingAndSortingRepository这个类的，

之后我按编辑器上面的黄线提示 自动填充了一段代码，JpaRepository把第二个OB改成Long类型的 编译通过，实际在运行中还是会出现这个错误，

那么按照源码里面的格式来一遍 ：

1.public interface UserRepository extends JpaRepository

2.public interface UserRepository extends JpaRepository

3.public interface UserRepository extends JpaRepository 

这三种都是可以的。之后实体也改成序列化的那种

public class User implements  java.io.Serializable

实际在运行前面那三种写法的时候就应经可以成功启动springboot了。

总结一波就是，写代码的时候不要涂省事 该写全就写全吧（ps这个demo是我download下来的 有可能是我本地环境问题也有可能是代码本身就有问题不能运行 我是改了之后可以的）

剩下就是对 泛型 序列化 以及对jpa的了解不深 需要好好看看了。