Spring教程访问数据jpa不起作用

Question

我使用 Spring，但从未尝试过 Spring Boot。我想尝试访问数据 jpa 教程 - https://spring.io/guides/gs/accessing-data-jpa/。我已经从 git 克隆了存储库，并按照教程中的描述使用 Maven 运行它： 混帐克隆https://github.com/spring-guides/gs-accessing-data-jpa.git mvnw spring-boot:run

运行这个，我得到一个错误 - Caused by: java.lang.ClassNotFoundException: org.springframework.data.repository.CrudRepository

为了解决这个问题，我添加了一个依赖项：

<dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-commons-core</artifactId>
            <version>1.4.1.RELEASE</version>
        </dependency>

这有帮助，但是，我遇到了另一个错误：

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 0 of method demo in hello.Application required a bean of type 'hello.CustomerRepository' that could not be found.


Action:

Consider defining a bean of type 'hello.CustomerRepository' in your configuration.

[WARNING]

java.lang.reflect.InvocationTargetException
        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.maven.AbstractRunMojo$LaunchRunner.run(AbstractRunMojo.java:527)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demo' defined in hello.Application: Unsatisfied dependency expressed through method 'demo' parameter 0; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'hello.CustomerRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:749)
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:467)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1173)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1067)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:737)
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:370)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:314)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1162)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1151)
        at hello.Application.main(Application.java:17)
        ... 6 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'hello.CustomerRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1486)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
        at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:835)
        at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:741)
        ... 24 more

我很惊讶 Spring 的官方教程不起作用。你试过这个教程吗？你有什么建议为什么它不起作用？是坏了还是我的机器出了什么问题？由于我对 Spring Boot 知之甚少，我不太确定问题可能出在哪里。

Answer 1

原来我的 Maven 存储库已损坏。删除它并下载所有内容的新副本会有所帮助。教程运行。