為什么通過Spring加載log4j2.xml會為log4j1類拋出NoClassDefFoundError？

Question

我正在將Spring 4 Web應用程序部署到Tomcat 8，並嘗試通過Spring加載log4j配置（ log4j2.xml ），以便可以將其存儲在WAR之外。 有了此配置，Spring在部署期間將為log4j1類（ org.apache.log4j.xml.DOMConfigurator ）拋出NoClassDefFoundError 。 但是，如果Log4j2位於類路徑中，則將正確加載它。 我的依存關系中沒有明確的logj1庫，只有log4j2。

用Spring初始化Log4J嗎？ 建議在web.xml中配置log4j。 我嘗試了此操作，但根本未加載log4j，並且未從應用程序中打印任何日志記錄語句。

在Spring中正確使用Log4jConfigurer建議在Tomcat中配置一個自定義log4j config文件名，但我所追求的不是。 給定文件名，我需要從WAR外部加載文件。

春季配置加載log4j2.xml：

<!-- Load Log4j config file via Spring -->
<bean id="log4jInitialization" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetClass" value="org.springframework.util.Log4jConfigurer"/>
    <property name="targetMethod" value="initLogging"/>
    <property name="arguments">
        <list>
            <value>${log4j.config.location}</value>
            <value>${log4j.refresh.interval}</value>
        </list>
    </property>
</bean>

完整堆棧跟蹤：

 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'log4jInitialization' defined in ServletContext resource [/WEB-INF/spring/root-context.xml]: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: org/apache/log4j/xml/DOMConfigurator
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:684)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4760)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5184)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:724)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:700)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:714)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:919)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1704)
    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.NoClassDefFoundError: org/apache/log4j/xml/DOMConfigurator
    at org.springframework.util.Log4jConfigurer.initLogging(Log4jConfigurer.java:102)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.util.MethodInvoker.invoke(MethodInvoker.java:269)
    at org.springframework.beans.factory.config.MethodInvokingBean.invokeWithTargetException(MethodInvokingBean.java:119)
    at org.springframework.beans.factory.config.MethodInvokingFactoryBean.afterPropertiesSet(MethodInvokingFactoryBean.java:106)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)

Answer 1

編輯：Log4jConfigurer不適用於log4j2，因為它依賴於（僅log4j1）DOMConfigurator類。 請從您的spring配置中刪除它。

而是使用log4j2提供的機制來控制配置文件的位置：系統屬性“ log4j.configurationFile”，或者參見Web應用程序log4j2手冊頁。