初学hibernate，所有的.jar都导入了，还是出现这个问题，该怎么解决啊，在线等！！！！
Exception in thread "main" java.lang.NoClassDefFoundError: org/hibernate/Session
at cn.itcast.hibernate.Base.addUser(Base.java:59)
at cn.itcast.hibernate.Base.main(Base.java:23)
Caused by: java.lang.ClassNotFoundException: org.hibernate.Session
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 2 more