This is just a guess, but is this "line 10" in your C0002_HomeAction class?
if((ses.get("context").toString()!="")&&(ses.get("role").toString()=="admin")){
Based on the exception, I'd say that the Session being null is what's
causing the exception. Try changing that line to
if((ses != null) &&
(ses.get("context").toString()!="")&&(ses.get("role").toString()=="admin")){
Another approach would be to implement an interceptor to check whether the
user is logged in -- if not, redirect them to the login page.
-Brian
On Sun, Nov 29, 2009 at 7:57 PM, Nguyen Xuan Son <yama...@gmail.com> wrote:
> dear all
> I have the C0002_Home.jsp and sessionChk.jsp files. The C0002_Home.jsp's
> source code is
> <s:action name="SessionCheck"></s:action>
>
> the meaning of this source code is to check users session whenever they
> enter the webpage
> the struts.xml is structured as:
> <action name="SessionCheck" class="com.baibai.action.SessionCheckAction">
> <result name="input">sessionChk.jsp</result>
> </action>
> <action name="C0002_Home" class="com.baibai.action.C0002_HomeAction">
> <result name="input">C0002_Home.jsp</result>
> </action>
>
> the detail of the SessionCheckAction.java file is
> public class SessionCheckAction extends ActionSupport{
> public String execute() throws Exception {
> Map ses = ActionContext.getContext().getSession();
>
> if((ses.get("context").toString()!="")&&(ses.get("role").toString()=="admin")){
> // the user is loginned as an administrator
> System.out.println("you have session");
> } else {
> System.out.println("you dont have session");
> }
> return SUCCESS;
> }
> }
>
> however when i tried to enter the C0002_Home.jsp without Login
> the error appears
> 2009/11/30 10:40:07
> com.opensymphony.xwork2.util.logging.commons.CommonsLogger error
> 致命的: Could not execute action: /SessionCheck
> java.lang.NullPointerException
> at com.baibai.action.SessionCheckAction.execute(SessionCheckAction.java:10)
> 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)
>
> this doesnt happen if I login into the system
> could you tell me where did I went wrong
>
> --
> =======================================================================
> Ritsumeikan University, Asia JinZai Project
> Master of Information Science
> Nguyen Xuan Son
>
> Add : Japan, Shiga-Ken, Kusatsu-Shi, Kasayama 3choume 1-18
> ShiteiHaimu
> Rien, Room 103
> Tel/Fax : 81-(0)90-3976 2246
> Email : nr000...@ed.ritsumei.ac.jp
> Mobile : 81-(0)90-3976 2246 URL : http://www.ritsumei.jp
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>
