我用tomcat5.5.25 和JDK 1.5的
配置好后 运行设计
出现了下列情况 是什么原因啊 谁能帮帮我

HTTP Status 500 - 

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type Exception report

message 

description The server encountered an internal error () that prevented it from fulfilling this request.

exception 

javax.servlet.ServletException
    org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:523)
    org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
    org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    com.DBWarehouse.util.Page_IdFilter.doFilter(Page_IdFilter.java:54)
    com.DBWarehouse.util.CharacterEncording.doFilter(CharacterEncording.java:32)


root cause 

java.lang.NullPointerException
    com.DBWarehouse.dao.impl.BaseDAO.querry(BaseDAO.java:51)
    com.DBWarehouse.dao.impl.UserDAO.getUserByLandIdPwd(UserDAO.java:39)
    com.DBWarehouse.struts.action.DoUserLoginAction.execute(DoUserLoginAction.java:44)
    org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
    org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    com.DBWarehouse.util.Page_IdFilter.doFilter(Page_IdFilter.java:54)
    com.DBWarehouse.util.CharacterEncording.doFilter(CharacterEncording.java:32)


note The full stack trace of the root cause is available in the Apache Tomcat/5.5.25 logs.


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Apache Tomcat/5.5.25