javax.- servlet.ServletException: java.lang.NullPointerException
Hier habe ich geschrieben, einige code für das abrufen der Werte aus der Datenbank übergeben einige Werte.
Unten ist die Action
class code:
AttendenceServiceImpl serveceimpl;
public ActionForward getStudentInfo(ActionMapping mapping,
ActionForm form, HttpServletRequest request,
HttpServletResponse response) {
System.out.println("-----------------getStudentInfo Start----------------------");
String category = request.getParameter("categoryVal");
String classId = request.getParameter("classidVal");
String sectionId = request.getParameter("sectionidVal");
System.out.println("----"+category+"---"+classId+"---"+sectionId);
serveceimpl.getStudentinfo(category,classId,sectionId);
Hier Category, classid
und section
Werte kommen.
Wird, und ich nenne die Methode der service
Klasse aus Action
Klasse.
Unten ist die Service
class code:
public List getStudentinfo(String category, String classId, String sectionId) {
System.out.println("------------getStudentinfo SERVICE START---------------------");
List data=mainpage.getStudentinfo(category, classId, sectionId);
System.out.println("------------getStudentinfo SERVICE END---------------------");
return data;
}
Aber in Action
Klasse, ich bin immer NullPointerException, bevor Sie die Kontrolle geben Sie in den Service
Klasse.
Unten ist die StackTrace:
-----------------getStudentInfo Start----------------------
----1---1---1
javax.servlet.ServletException: java.lang.NullPointerException
at org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:520)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:427)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.centris.campus.admin.AuthuFilter.doFilter(AuthuFilter.java:232)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
at com.centris.campus.actions.AttendenceAction.getStudentInfo(AttendenceAction.java:58)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
... 24 more
Apr 10, 2014 12:44:47 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [action] in context with path [/e-CampusPro] threw exception [java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at com.centris.campus.actions.AttendenceAction.getStudentInfo(AttendenceAction.java:58)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:269)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:170)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:425)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:228)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.centris.campus.admin.AuthuFilter.doFilter(AuthuFilter.java:232)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Bitte geben Sie mir die Lösung, es ist hilfreich für mich.
Du musst angemeldet sein, um einen Kommentar abzugeben.
serveceimpl
solltenull
hier. Bitte überprüfen Sie ob Sie einen gültigen Wert in es. Siehe untenDu Sie noch nicht initialisiert, es
AttendenceServiceImpl serveceimpl;