实现 Spring Data Repositories 接口抛出异常“org.springframework.beans.factory.BeanCreationException”答案

【问题标题】：Implementing Spring Data Repositories Interface throws an Exception "org.springframework.beans.factory.BeanCreationException"实现 Spring Data Repositories 接口抛出异常“org.springframework.beans.factory.BeanCreationException”
【发布时间】：2021-02-22 02:57:29
【问题描述】：

我正在尝试为一个简单的 Web 应用程序创建一个存储库。似乎导入和使用 import org.springframework.data.repository.CrudRepository 会导致错误。我不确定如何开始调试收到的错误消息。

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'roomRepository' defined in main.behavior.RoomRepository defined in @EnableJpaRepositories declared on JpaRepositoriesRegistrar.EnableJpaRepositoriesConfiguration: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: kotlin/reflect/full/KClasses
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1794) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:226) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:624) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeansOfType(DefaultListableBeanFactory.java:612) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.data.repository.config.DeferredRepositoryInitializationListener.onApplicationEvent(DeferredRepositoryInitializationListener.java:51) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.repository.config.DeferredRepositoryInitializationListener.onApplicationEvent(DeferredRepositoryInitializationListener.java:36) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:898) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554) ~[spring-context-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at main.ApplicationKt.main(Application.kt:13) ~[classes/:na]
Caused by: java.lang.NoClassDefFoundError: kotlin/reflect/full/KClasses
    at org.springframework.data.mapping.model.PreferredConstructorDiscoverer$Discoverers$2.lambda$discover$3(PreferredConstructorDiscoverer.java:163) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at java.base/java.util.Optional.orElseGet(Optional.java:369) ~[na:na]
    at org.springframework.data.mapping.model.PreferredConstructorDiscoverer$Discoverers$2.discover(PreferredConstructorDiscoverer.java:160) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.model.PreferredConstructorDiscoverer.discover(PreferredConstructorDiscoverer.java:79) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.model.BasicPersistentEntity.<init>(BasicPersistentEntity.java:105) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.jpa.mapping.JpaPersistentEntityImpl.<init>(JpaPersistentEntityImpl.java:59) ~[spring-data-jpa-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.createPersistentEntity(JpaMetamodelMappingContext.java:70) ~[spring-data-jpa-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.createPersistentEntity(JpaMetamodelMappingContext.java:44) ~[spring-data-jpa-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.context.AbstractMappingContext.addPersistentEntity(AbstractMappingContext.java:372) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.context.AbstractMappingContext.getPersistentEntity(AbstractMappingContext.java:263) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.context.AbstractMappingContext.getPersistentEntity(AbstractMappingContext.java:206) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.mapping.context.AbstractMappingContext.getPersistentEntity(AbstractMappingContext.java:90) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.lambda$afterPropertiesSet$4(RepositoryFactoryBeanSupport.java:295) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at java.base/java.util.Optional.ifPresent(Optional.java:183) ~[na:na]
    at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:295) ~[spring-data-commons-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:144) ~[spring-data-jpa-2.3.3.RELEASE.jar:2.3.3.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1853) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1790) ~[spring-beans-5.2.8.RELEASE.jar:5.2.8.RELEASE]
    ... 25 common frames omitted
Caused by: java.lang.ClassNotFoundException: kotlin.reflect.full.KClasses
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581) ~[na:na]
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) ~[na:na]
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) ~[na:na]
    ... 43 common frames omitted


Process finished with exit code 1

这是我的实体

package main.behavior

import javax.persistence.Column
import javax.persistence.Entity
import javax.persistence.Id
import javax.persistence.Table

@Entity
@Table(name = "rooms")
class Room {
        @Id
        lateinit var id: String
        @Column(name = "user1", nullable = true)
        lateinit var user1: String
}

这是我的仓库

package main.behavior

import org.springframework.data.repository.CrudRepository

interface RoomRepository : CrudRepository<Room, String>

这是我的控制器

package main.endpoints

import main.behavior.Room
import main.behavior.RoomRepository
import org.springframework.web.bind.annotation.*

@RestController
class CreateRoom(private val repo: RoomRepository){
    @RequestMapping("/rooms/create{id}")
    @ResponseBody
    fun createRoom(@RequestParam(value = "id", required = true) id: String): String {
        println("id: $id")
        val room = Room().also{
            room ->  room.id = id
            room.user1 = "user1"
        }
        repo.save(room)
        return "room created"
    }
}

还有我的 pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.3.RELEASE</version>
    </parent>
    <groupId>com.example</groupId>
    <artifactId>spring-boot</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot</name>

    <properties>
        <java.version>1.8</java.version>
        <kotlin.version>1.4.20-RC</kotlin.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-stdlib-jdk8</artifactId>
            <version>${kotlin.version}</version>
        </dependency>
        <dependency>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-test</artifactId>
            <version>${kotlin.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.2.18</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>



    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <version>${kotlin.version}</version>
                <executions>
                    <execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>test-compile</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>test-compile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <jvmTarget>1.8</jvmTarget>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <executions>
                    <execution>
                        <id>default-compile</id>
                        <phase>none</phase>
                    </execution>
                    <execution>
                        <id>default-testCompile</id>
                        <phase>none</phase>
                    </execution>
                    <execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>testCompile</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

【问题讨论】：

java.lang.NoClassDefFoundError 表示在运行时找不到类。你是如何运行应用程序的？通过 Maven 或通过 IDE 的命令行？
@WimDeblauwe 我在 Intellij Ultimate 的 Spring Boot 配置中运行它
也许在命令行上试试mvn spring-boot:run 看看有没有区别。如果这有效，那么您的 IntelliJ 设置有问题。您可以尝试重新导入 Maven 项目。
另外，看看这个问题，也许有用：stackoverflow.com/questions/47174036/…

标签： java spring spring-boot maven kotlin

【解决方案1】：

您缺少一个依赖项：

    <dependency>
      <groupId>org.jetbrains.kotlin</groupId>
      <artifactId>kotlin-reflect</artifactId>
      <version>${kotlin.version}</version>
    </dependency>

这个依赖帮助 Spring 创建 bean。有关此的更多信息，请查看文档：https://kotlinlang.org/docs/reference/reflection.html

【讨论】：

你是一个救生员。我在 springs 文档中注意到了这种依赖关系，但认为我不需要它。谢谢
我有一个非常相似的问题，并认为这是一个 Spring Boot 问题，即没有从库中找到 JPA 存储库和实体。尝试在@SpringBootApplication 中设置scanBasePackages 并明确定义@EntityScan 和@EnableJpaRepositories，但这一切都没有帮助。原来 Repository 和 Entity 类无法实例化，因为缺少对 kotlin-reflect 的依赖。谢谢！！！顺便说一句：我发现以下帖子很有帮助：stackoverflow.com/questions/41815871/…