Log4j问题求助！！

Struts包中不是已经包含commons.logging.jar这个文件了吗
为什么还报下面的异常
java.lang.ClassNotFoundException: 
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at org.apache.commons.logging.impl.LogFactoryImpl$1.run(LogFactoryImpl.java:447)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.commons.logging.impl.LogFactoryImpl.loadClass(LogFactoryImpl.java:435)
at org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:376)
at org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
at org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
at org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
at org.apache.struts.action.ActionServlet.<clinit>(ActionServlet.java:226)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1104)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:981)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4044)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4350)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:761)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:741)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:825)
at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:714)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:490)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:120)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1023)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1015)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:448)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
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:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
我在action中写入下内容：
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
Log log=LogFactory.getLog(this.getClass());
log.debug("This is a debug message!");
log.trace("This is a trace message!");
log.info("This is a info message!");
log.warn("This is a warn message!");
log.error("This is a error message");
log.fatal("This is a fatal message");在commons-logging.properties中
  org.apache.commons.logging.Log
   =org.apache.commons.logging.impl.Log4JCategoryLog;
 log4j.rootLogger=INFO,console,file
   # define a appender named console,which is set to be a ConsoleAppender
      log4j.appender.console=org.apache.log4j.ConsoleAppender
       # define a appender named file,which is set to be a RollingFileAppender
      log4j.appender.file=org.apache.log4j.RollingFileAppender
      log4j.appender.file.File=log.txt
      log4j.appender.console.layout=org.apache.log4j.SimpleLayout
      
       # Assign a PatternLayout to file appender
       log4j.appender.file.layout=org.apache.log4j.PatternLayout
      log4j.appender.file.layout.ConversionPattern=%t %p- %m%n