tomcat提示找不到log4j问题

今天在设置applet程序的本地引用包，设置完成后，发现web程序运行不起来，一直报错:
org.apache.commons.logging.LogConfigurationException:   org.apache.commons.logging.LogConfigurationException:   No   suitable   Log   constructor   [Ljava.lang.Class;@13dcd27   for   org.apache.commons.logging.impl.Log4JLogger
at   org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:532)
at   org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:272)
at   org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:246)
at   org.apache.commons.logging.LogFactory.getLog(LogFactory.java:395)
at   org.apache.catalina.session.ManagerBase. <init> (ManagerBase.java:63)
at   org.apache.catalina.session.StandardManager. <init> (StandardManager.java:64)
at   org.apache.catalina.startup.ContextConfig.managerConfig(ContextConfig.java:317)
at   org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:638)
at   org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:216)
at   org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at   org.apache.catalina.core.StandardContext.start(StandardContext.java:4270)
at   org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:823)
at   org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:807)
at   org.apache.catalina.core.StandardHost.addChild(StandardHost.java:595)
at   org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:277)
at   org.apache.catalina.core.StandardHost.install(StandardHost.java:832)
at   org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:701)
at   org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:432)
at   org.apache.catalina.startup.HostConfig.start(HostConfig.java:983)
at   org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:349)
at   org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at   org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1091)
at   org.apache.catalina.core.StandardHost.start(StandardHost.java:789)
at   org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1083)
at   org.apache.catalina.core.StandardEngine.start(StandardEngine.java:478)
at   org.apache.catalina.core.StandardService.start(StandardService.java:480)
at   org.apache.catalina.core.StandardServer.start(StandardServer.java:2313)
at   org.apache.catalina.startup.Catalina.start(Catalina.java:556)
at   sun.reflect.NativeMethodAccessorImpl.invoke0(Native   Method)
at   sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at   sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at   java.lang.reflect.Method.invoke(Method.java:324)
at   org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:287)
at   org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:425)
Caused   by:   org.apache.commons.logging.LogConfigurationException:   No   suitable   Log   constructor   [Ljava.lang.Class;@13dcd27   for   org.apache.commons.logging.impl.Log4JLogger
at   org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:432)
at   org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:525)
...   33   more
Caused   by:   java.lang.NoClassDefFoundError:   org/apache/log4j/Logger
at   java.lang.Class.getDeclaredConstructors0(Native   Method)
at   java.lang.Class.privateGetDeclaredConstructors(Class.java:1610)
at   java.lang.Class.getConstructor0(Class.java:1922)
at   java.lang.Class.getConstructor(Class.java:1019)
at   org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:429)
...   34   more


查找了lib，明明有引用log4j的包，也有commons-logging.jar包，但一直提示找不到这个包。试了下以前的web程序，同样报这样的错误，运行不起来。google了一翻，没有能有具体的解决办法，后来想想是不是因为设置了jre/lib/applet和jre/lib/ext包的问题。重新设置jdk1.6的classpath和设置tomcat的jdk位置，从新运行，一切OK.