java - Kotlin + Spring Boot，找不到 bean

Question

我刚刚开始学习Kotlin和Spring Boot，并且已经基于在线教程完成了实现。但是它无法运行并打印如下内容:

Description:

Parameter 0 of constructor in com.jacksonhu.slientshare.controller.ForumController required a bean of type 'com.jacksonhu.slientshare.repository.ArticleRepo' that could not be found.


Action:

Consider defining a bean of type 'com.jacksonhu.slientshare.repository.ArticleRepo' in your configuration.

所以我四处搜寻，找到了一些解决方法的话题。因此，我在 @EnableJpaRepositories(basePackages = ["com.jacksonhu.slientshare.repository"])下方添加了一行注释 @SpringBootApplication。然后抛出一个新的异常:

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'forumController' defined in file [/Users/hu/Projects/SlientShare/out/production/classes/com/jacksonhu/slientshare/controller/ForumController.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'articleRepo': Post-processing of merged bean definition failed; nested exception is java.lang.NoClassDefFoundError: javax/persistence/SynchronizationType
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:729) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:192) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1270) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1127) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:541) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.1.RELEASE.jar:2.0.1.RELEASE]
    at com.jacksonhu.slientshare.SlientshareApplicationKt.main(SlientshareApplication.kt:19) [classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'articleRepo': Post-processing of merged bean definition failed; nested exception is java.lang.NoClassDefFoundError: javax/persistence/SynchronizationType
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:501) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:815) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:721) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    ... 18 common frames omitted
Caused by: java.lang.NoClassDefFoundError: javax/persistence/SynchronizationType
    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor$PersistenceElement.<init>(PersistenceAnnotationBeanPostProcessor.java:653) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.lambda$buildPersistenceMetadata$1(PersistenceAnnotationBeanPostProcessor.java:435) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.util.ReflectionUtils.doWithLocalMethods(ReflectionUtils.java:522) ~[spring-core-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.buildPersistenceMetadata(PersistenceAnnotationBeanPostProcessor.java:420) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.findPersistenceMetadata(PersistenceAnnotationBeanPostProcessor.java:394) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(PersistenceAnnotationBeanPostProcessor.java:332) ~[spring-orm-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:1016) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    ... 28 common frames omitted
Caused by: java.lang.ClassNotFoundException: javax.persistence.SynchronizationType
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_161]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_161]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338) ~[na:1.8.0_161]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_161]
    ... 36 common frames omitted

所以我只是想知道我是否误解了什么？还是我的配置错误？

我的gradle配置在这里:

buildscript {
    ext {
        kotlinVersion = '1.2.40'
        springBootVersion = '2.0.1.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
        classpath("org.jetbrains.kotlin:kotlin-allopen:${kotlinVersion}")
    }
}

apply plugin: 'kotlin'
apply plugin: 'kotlin-spring'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'

group = 'com.jacksonhu'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
compileKotlin {
    kotlinOptions {
        freeCompilerArgs = ["-Xjsr305=strict"]
        jvmTarget = "1.8"
    }
}
compileTestKotlin {
    kotlinOptions {
        freeCompilerArgs = ["-Xjsr305=strict"]
        jvmTarget = "1.8"
    }
}

repositories {
    mavenCentral()
}


dependencies {
    compile('org.springframework.boot:spring-boot-starter-security')
    compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    compile("org.jetbrains.kotlin:kotlin-reflect")
    compile group: 'javax.persistence', name: 'persistence-api', version: '1.0'
    compile group: 'org.springframework.data', name: 'spring-data-jpa', version: '2.0.6.RELEASE'
    compile group: 'javax.validation', name: 'validation-api', version: '2.0.1.Final'
    runtime('mysql:mysql-connector-java')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    testCompile('org.springframework.security:spring-security-test')
}

...以及我的主要类(class):

package com.jacksonhu.slientshare

import org.springframework.boot.SpringApplication

import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.context.annotation.ComponentScan
import org.springframework.data.jpa.repository.config.EnableJpaRepositories

@SpringBootApplication
@ComponentScan(basePackages = ["com.jacksonhu.slientshare"])
@EnableJpaRepositories(basePackages = ["com.jacksonhu.slientshare.repository"])
class SlientshareApplication

fun main(args: Array<String>) {
    runApplication<SlientshareApplication>(*args)
}

...以及整个包装结构:



如果有人需要查看我的代码，则为: https://github.com/huming2207/SlientShare

Answer 1

您错过了一些依赖项:

dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
    compile('org.springframework.boot:spring-boot-starter-security')
    compile('org.springframework.boot:spring-boot-starter-data-jpa')

    compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
    compile("org.jetbrains.kotlin:kotlin-reflect")

    compile group: 'javax.xml.bind', name: 'jaxb-api', version: '2.3.0'
    compile group: 'org.hibernate.javax.persistence', name: 'hibernate-jpa-2.1-api', version: '1.0.2.Final'
    compile group: 'javax.validation', name: 'validation-api', version: '2.0.1.Final'
    runtime('mysql:mysql-connector-java')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    testCompile('org.springframework.security:spring-security-test')
}

;添加此依赖项后，我从GitHub克隆了您的代码，它可以正常工作。