请教~~~~~~

进入到输入http://localhost:8080打开正常

进入Tomcat Manager输入用户名弹出考试系统的登入界面

然后输入用户名：tsoft，密码：111后，但是显示以下内容，请问怎么解决？！！！！前台后台都是如此
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: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
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)


root cause 

java.lang.NullPointerException
com.wgh.core.ConnDB.executeQuery(ConnDB.java:57)
com.wgh.dao.ManagerDAO.checkManager(ManagerDAO.java:15)
com.wgh.action.Manager.managerLogin(Manager.java:44)
com.wgh.action.Manager.execute(Manager.java:22)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
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)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.10 logs.


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Apache Tomcat/6.0.10