考虑在配置中创建类型 "[class]" 的 Bean

Question

我一直在尝试创建一个 CRUD 应用程序，但是当我尝试运行该应用程序时，我收到错误"Field repo in com.nationwide.individualproject.controllers.BoulderController required a bean of type 'com.nationwide.individualproject.Repos.BoulderRepo' that could not be found." 以及标题中的消息。

我尝试添加各种注释，例如@ComponantScan和@EntityScan但这并没有改变任何东西。该应用程序由三个包组成，全部在com.nationwide.individualproject; .controllers, .data, .Repos下，每个类分别被注释为@RestController, @Entity, and @Repository。

主应用程序类位于同一级别的所有这些包之外。

主要应用程序如下所示：

package com.nationwide.individualproject;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication()
public class IndividualProjectApplication {
public static void main(String[] args) {
SpringApplication.run(IndividualProjectApplication.class, args);
}
}

BoulderRepo看起来像：

package com.nationwide.individualproject.Repos;
import com.nationwide.individualproject.data.Boulder;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import java.util.ArrayList;
import java.util.Date;
@Repository
public interface BoulderRepo extends JpaRepository<Boulder, Integer> {
...
}

博尔德类看起来像：

package com.nationwide.individualproject.data;
import javax.persistence.Entity;
import javax.persistence.Id;
import java.util.Date;
@Entity
public class Boulder {
@Id
...
}

最后，控制器看起来像：

package com.nationwide.individualproject.controllers;
import com.nationwide.individualproject.Repos.BoulderRepo;
import com.nationwide.individualproject.data.Boulder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.Date;
@RestController
public class BoulderController {
@Autowired
private BoulderRepo repo;
...
}

查看与我类似的其他问题，他们建议这与将类全部放在不同的包中有关，但我仍然不确定为什么当主类与所有包处于同一级别时会出现错误。

项目结构的视觉效果如下所示：

---com.nationwide.individualproject
---controllers
---data
---Repos
---individualProjectApplication

编辑更长的堆栈跟踪消息

2019-10-21 14:04:21.705  INFO 3172 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2019-10-21 14:04:21.716  WARN 3172 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'boulderController': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.nationwide.individualproject.Repos.BoulderRepo' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
Related cause: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'speedRepo': Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
Related cause: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'boulderRepo': Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
Related cause: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'topRopeRepo': Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
Related cause: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'leadRepo': Could not resolve matching constructor (hint: specify index/type/name arguments for simple parameters to avoid type ambiguities)
2019-10-21 14:04:21.717  INFO 3172 --- [           main] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2019-10-21 14:04:21.720  INFO 3172 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2019-10-21 14:04:21.732  INFO 3172 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
2019-10-21 14:04:21.735  INFO 3172 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2019-10-21 14:04:21.746  INFO 3172 --- [           main] ConditionEvaluationReportLoggingListener : 
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-10-21 14:04:21.849 ERROR 3172 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 
***************************
APPLICATION FAILED TO START
***************************
Description:
Field repo in com.nationwide.individualproject.controllers.BoulderController required a bean of type 'com.nationwide.individualproject.Repos.BoulderRepo' that could not be found.
The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)

Action:
Consider defining a bean of type 'com.nationwide.individualproject.Repos.BoulderRepo' in your configuration.

Answer 1

您的pom.xml文件中存在版本问题 从下面的代码中删除版本。

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>2.0.1.RELEASE</version>
</dependency>

它应该像

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
</dependency>