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 =======================================================================