tomcat中测试项目

我现在有一个项目的源码，拷到了Tomcat安装路径下的webapps文件夹中，输入http://localhost:8080/进入那个管理界面后，点Tomcat Manager后进入一个Tomcat程序应用管理界面，其中就有我刚拷的那个文件夹，点击后就出来我的项目的登录界面了，但点击登录后就出错了，下面是出错信息：
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.struts.filter.MyFilter.doFilter(MyFilter.java:15)
root cause java.lang.NullPointerException
com.hiernate.util.HibernateUtil.findUser(HibernateUtil.java:27)
com.struts.action.FindUserAction.finUser(FindUserAction.java:23)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:280)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:216)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
com.struts.filter.MyFilter.doFilter(MyFilter.java:15)请大家帮帮我啊~~~是什么原因啊?怎么解决？ 我是新手，请大家说详细一点啊 谢谢~~~