出现错误500，请问问题出在哪儿，在线等
HTTP Status 500 - 

--------------------------------------------

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: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:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)


root cause 

java.lang.NullPointerException
com.hfut.oa.dao.DB.getRs(DB.java:66)
com.hfut.oa.action.LogonAction.executeLogonNo(LogonAction.java:74)
com.hfut.oa.action.LogonAction.execute(LogonAction.java:31)
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:637)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.29 logs.


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Apache Tomcat/6.0.29

------解决方案--------------------
java.lang.NullPointerException
com.hfut.oa.dao.DB.getRs(DB.java:66)

空指针异常，看看代码啥样先。
------解决方案--------------------
请将这一行标注一下com.hfut.oa.dao.DB.getRs(DB.java:66)

我的异常网推荐解决方案：The server encountered an internal error () that prevented it from fulfilling this request.,http://www.aiyiweb.com/java-web/317.html