eclipse - org.apache.commons.io.output.ByteArrayOutputStream 顽固的 ClassNotFoundException

Question

一段时间以来，我一直在 eclipse 中运行相同的 Web 应用程序，并大量使用 org.apache.commons.io.output.ByteArrayOutputStream。
出乎意料的是，尽管 commons-io-2.4.jar 包含在构建路径中并标记为已导出，但该项目现在抛出 ClassNotFoundException。
这个类已经使用了一段时间，因此出现了难题

我可以做些什么来确保找到该类？

编辑:我有两台配置了 Tomcat 7.0.40 和 Tomcat 6.0.33 的服务器
该问题仅在 Tomcat 7 上出现。

注意:已尝试以下解决方法:

1. 重新启动 Eclipse。
2. 清理项目
3. 删除并重新添加 commons-io-2.4.jar

堆栈跟踪:

SEVERE: A child container failed during startjava.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WebApp]]    at java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source)    at java.util.concurrent.FutureTask.get(Unknown Source)    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:800)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)    at java.util.concurrent.FutureTask$Sync.innerRun(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: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/WebApp]]    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)    ... 7 moreCaused by: java.lang.NoClassDefFoundError: org/apache/commons/io/output/ByteArrayOutputStream    at java.lang.Class.getDeclaredFields0(Native Method)    at java.lang.Class.privateGetDeclaredFields(Unknown Source)    at java.lang.Class.getDeclaredFields(Unknown Source)    at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)    at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:261)    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:140)    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:67)    at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:405)    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:881)    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:369)    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5269)    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)    ... 7 moreCaused by: java.lang.ClassNotFoundException: org.apache.commons.io.output.ByteArrayOutputStream    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714)    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)    ... 21 more

Answer 1

问题已通过从 Eclipse 中删除 Tomcat 7.0 实例 并将其添加回来
解决我只能猜测服务器配置有时会损坏