纬度是怎么算出来的:点击登陆界面的登录命令，出现javax.servlet.ServletException错误，请问是怎么回事？

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
at org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)

root cause

java.lang.NullPointerException
at com.szypt.web.LoginAction.logon(LoginAction.java:116)
at com.szypt.web.LoginAction.execute(LoginAction.java:59)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at com.szypt.common.Controller.process(Controller.java:36)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)