Java 尝试学习Spring:BeanCreationException:创建名为的bean时出错

开始学习“行动中的春天”，第一章就遇到了麻烦。 我有一个使用Maven构建的简单Spring应用程序：

pom.xml

4.0.0
org.alesto
春季研究
1
org.mockito
莫基托磁芯
2.0.41-beta
朱尼特
朱尼特
4.12
org.springframework
spring上下文
4.2.4.1发布

我在XML应用程序上下文中定义了三个bean：

正如你所看到的，我已经尝试在

之前和
之后插入两个特定方法的调用，它们的id是“bounk”。正是这部分代码（aop）导致了
BeanCreationException
：

    Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'knight' defined in class path resource [main/resources/spring/knight.xml]: BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0': Cannot create inner bean '(inner bean)#7ea9e1e2' of type [org.springframework.aop.aspectj.AspectJMethodBeforeAdvice] while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#7ea9e1e2': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:478)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at main.java.alesto.knight.KnightMain.main(KnightMain.java:7)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.aop.aspectj.AspectJPointcutAdvisor#0': Cannot create inner bean '(inner bean)#7ea9e1e2' of type [org.springframework.aop.aspectj.AspectJMethodBeforeAdvice] while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#7ea9e1e2': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:313)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:129)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:648)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:140)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.aop.framework.autoproxy.BeanFactoryAdvisorRetrievalHelper.findAdvisorBeans(BeanFactoryAdvisorRetrievalHelper.java:92)
    at org.springframework.aop.framework.autoproxy.AbstractAdvisorAutoProxyCreator.findCandidateAdvisors(AbstractAdvisorAutoProxyCreator.java:101)
    at org.springframework.aop.aspectj.autoproxy.AspectJAwareAdvisorAutoProxyCreator.shouldSkip(AspectJAwareAdvisorAutoProxyCreator.java:103)
    at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessBeforeInstantiation(AbstractAutoProxyCreator.java:248)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:988)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.resolveBeforeInstantiation(AbstractAutowireCapableBeanFactory.java:959)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:472)
    ... 10 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#7ea9e1e2': Cannot resolve reference to bean 'embark' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:634)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:140)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:299)
    ... 28 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'embark': Instantiation of bean failed; nested exception is java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:325)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
    ... 36 more
Caused by: java.lang.NoClassDefFoundError: org/aspectj/weaver/reflect/ReflectionWorld$ReflectionWorldException
    at java.lang.Class.getDeclaredConstructors0(Native Method)
    at java.lang.Class.privateGetDeclaredConstructors(Class.java:2671)
    at java.lang.Class.getConstructor0(Class.java:3075)
    at java.lang.Class.getDeclaredConstructor(Class.java:2178)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:80)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098)
    ... 42 more
Caused by: java.lang.ClassNotFoundException: org.aspectj.weaver.reflect.ReflectionWorld$ReflectionWorldException
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 48 more

任务本身：

package main.java.alesto.knight;

public class BraveKnight implements Knight {

    private Quest quest;

    //We are going to inject a quest via Spring using CONSTRUCTOR INJECTION
    public BraveKnight(Quest quest) {
        this.quest = quest;
    }

    public void embarkOnQuest() {
        quest.embark();
    }
}

package main.java.alesto.knight;

import java.io.PrintStream;

public class SlayDragonQuest implements Quest {

    private PrintStream stream;

    //We are going to inject a quest via Spring using CONSTRUCTOR INJECTION
    public SlayDragonQuest(PrintStream stream) {
        this.stream = stream;
    }

    public void embark() {
        stream.println("Embarking on quest to slay the dragon!");
    }
}

与骑士合作的吟游诗人，他根据骑士的行动唱歌：

package main.java.alesto.knight;

import java.io.PrintStream;

public class Minstrel {

    private PrintStream printStream;

    public Minstrel(PrintStream printStream) {
        this.printStream = printStream;
    }

    public void singBeforeQuest() {
        printStream.println("This piece of shit is going to dieeeeee!!11");
    }

    public void singAfterQuest() {
        printStream.println("The noble hero brought the victory!");
    }
}

我为什么会遇到此异常以及如何解决它？
您遇到的错误是：

原因：java.lang.ClassNotFoundException:org.aspectj.weaver.reflect.ReflectionWorld$ReflectionWorldException

这意味着您的应用程序缺少必需的库。在您的例子中，您正在使用Spring（
）执行AOP，因此需要将Spring AOP添加到Maven POM中：


org.springframework
春季aop
4.2.4.1发布


作为旁注，我注意到您依赖于Mockito和JUnit，其默认范围为
compile
scope。因为这些可能是测试依赖项，所以最好使用
test
范围声明它们：


org.mockito
莫基托磁芯
2.0.41-beta
测试
朱尼特
朱尼特
4.12
测试
添加cglib参考，如下所示：
编译组：“cglib”，名称：“cglib”，版本：“3.2.5”
然后在命令行中运行gradlebuild，然后运行程序，一切都会好起来的
 我和你有同样的问题。解决方案：您需要AspectJ库

<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-aop -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
    <version>2.3.3.RELEASE</version>
</dependency>


org.springframework.boot
弹簧启动机aop
2.3.3.2发布
您缺少AOP（）对maven的依赖性。另见：谢谢！不幸的是，书中的样本是用Gradle构建的，我对它并不熟悉。不过，你的建议并没有完全起作用。考虑到你的建议，我还必须为“SpringAspects”添加依赖项。直到那时，事情才顺利进行。