HIBERNATE 怎么在服务器上运行不起啊？

java.lang.NullPointerException
userlogin.HibernateUtil.currentSession(HibernateUtil.java:24)
userlogin.User.save(User.java:17)
userlogin.RegistAction.execute(RegistAction.java:42)
org.apache.struts.action.RequestProcessor.processActionPerform
HibernateUtil这里面报的空指针，自己查吧