Question

启动Tomcat时，我得到了一些这样的异常：

java.lang.NoClassDefFoundError: com/mycompany/mypackage/SomeClass
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.getDeclaredMethods(Unknown Source)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.buildLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:194)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.findLifecycleMetadata(InitDestroyAnnotationBeanPostProcessor.java:176)
at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(InitDestroyAnnotationBeanPostProcessor.java:122)
at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessMergedBeanDefinition(CommonAnnotationBeanPostProcessor.java:283)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyMergedBeanDefinitionPostProcessors(AbstractAutowireCapableBeanFactory.java:870)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:495)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:410)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5003)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5517)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1263)
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1948)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: com.mycompany.mypackage.SomeClass
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1858)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1709)
... 33 more

所以，这意味着，Spring无法初始化某个bean，因为它直接（或者更糟，间接）引用了类com.mycompany.mypackage.SomeClass

我发现这个Stacktrace非常糟糕，因为它告诉了症状，但不是根本原因。我需要知道什么bean没有被初始化，所以我可以和负责那个bean的人交谈，这样他就可以决定是否应该在类路径中使用“SomeClass”。

是否有任何技巧可以找出未初始化的bean？

Answer 1

在debug上将日志记录级别设置为org.springframework，您将获得有关此异常发生位置的更详细日志。

Answer 2

我从未在识别失败的bean时遇到任何问题，它们始终显示在 log4j 文件中。它显示了错误的确切原因，例如：

o.s.w.s.DispatcherServlet ERROR - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'homeController' defined in file [...\HomeController.class]: Instantiation of bean failed; nested exception is java.lang.ExceptionInInitializerError
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1095)
    ...
    Caused by: java.lang.ClassNotFoundException: NonExistent
    at java.lang.Class.forName(Class.java:240)
    at .......HomeController.<clinit>(HomeController.java:17)

获取更详细的Spring Bean初始化异常

2 个答案: