下午学习hibernate缓存机制的时候遇到了一个这样的异常：java.lang.NoClassDefFoundError:org/apache/commons/logging/LogFactory。最后排除原因，寻到了解决答案，原因是缓存机制需要ehcache.jar包，同时也需要commons.loggin.jar包，下边详细介绍一下
工具/原料
hibernate缓存机制
异常详细预览：
1、java.lang.N艺皱麾酪oClassDefFoundError:org/apache/commons/logging/LogFa艘早祓胂ctoryatnet.sf.ehcache.CacheManager.<clinit>(CacheManager.java:65)atorg.hibernate.cache.EhCacheProvider.start(EhCacheProvider.java:131)atorg.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge.start(RegionFactoryCacheProviderBridge.java:72)atorg.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:221)atorg.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341)atcom.gis520.sessionFactory.HibernateSessionFactory.<clinit>(HibernateSessionFactory.java:31)atcom.gis520.test.EmpTest.testSelect(EmpTest.java:22)atsun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethod)atsun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)atsun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)atjava.lang.reflect.Method.invoke(Method.java:597)atorg.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)atorg.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)atorg.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)atorg.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)atorg.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)atorg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)atorg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)atorg.junit.runners.ParentRunner$3.run(ParentRunner.java:193)atorg.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)atorg.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)atorg.junit.runners.ParentRunner.access$000(ParentRunner.java:42)atorg.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)atorg.junit.runners.ParentRunner.run(ParentRunner.java:236)atorg.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)atorg.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)atorg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)atorg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)atorg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)atorg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)Causedby:java.lang.ClassNotFoundException:org.apache.commons.logging.LogFactoryatjava.net.URLClassLoader$1.run(URLClassLoader.java:200)atjava.security.AccessController.doPrivileged(NativeMethod)atjava.net.URLClassLoader.findClass(URLClassLoader.java:188)atjava.lang.ClassLoader.loadClass(ClassLoader.java:307)atsun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)atjava.lang.ClassLoader.loadClass(ClassLoader.java:252)atjava.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)...30more
异常解决方案
1、出现以上的异常是由于缺潢舵猥妒少一个commons-logging的jar包，commons-logging缕计瓤账.jar包的作用可以说是和Log4j.jar类似，都是对日记处理等。但是工程里边已经有了log4j.jar了还是报这个错，我也纳闷，是一定需要commons-logging.jar包吧。。小编也是初学者，待得知答案再告诉大家。或者大家知道答案的评论一下哦。一起学习。网上下载一个commons-logging。jar包
2、将包拷贝到工程的lib文件下——》addtobuildpath
3、添加好后运行程序即可发现解决了异常、
