Cannot get attribute from session in Struts 2

Question

I am new to Struts2 and I am trying to retrieve an attribute I set in the action class.

LoginAction.java:

public class LoginAction extends ActionSupport implements SessionAware {
    private static final long serialVersionUID = 1L;

    private Map<String, Object> session;

    // field variables

    @Override
    public String execute() {
        UserManager um = new UserManager();
        String registeredPassword = um.getCurrentUserDetail("user_password", getUserId());

        if(getUserPassword().equals(registeredPassword)) {
            String currentUserId = um.getCurrentUserDetail("user_id", userId);
            int currentUserType = um.getCurrentUserType(userId);

            session.put("currentUserId", (String) currentUserId);
            session.put("currentUserType", (Integer) currentUserType);

            System.out.println("You have successfully logged in!");
            return SUCCESS;
        }

        System.out.println("Your login has failed!");
        return ERROR;
    }

    @Override
    public void setSession(Map<String, Object> session) {
        this.session = session;
    }

    // getters and setters
}

struts.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>
    <package name="default" extends="struts-default">
        <action name="login" class="com.mypackage.model.LoginAction">
            <result name="success">/index.jsp</result>
            <result name="error">/login.jsp</result>
        </action>
    </package>
</struts>

index.jsp:

<%@ taglib prefix="s" uri="/struts-tags"%>
<%@ page import="com.mypackage.model.LoginAction" %>

<head>    
<%
    int type = 0;

    if(session.containsKey("currentUserType")) {
        type = (Integer) session.get("currentUserType");
    }
%>
</head>

However, the methods containsKey() and get() are returning undefined for session. How do I get the attributes that was put in session in Struts2?

if he uses value, then he needs to specify name too. key = label+value+name — Andrea Ligios, Nov 13 '14 at 16:49

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

It's happening because from Scriptlet you are reading the HttpSession, not the wrapping Struts2 SessionMap. You can read more info here.

But do yourself a favor and avoid using scriptlet completely, forever. And ever.

Assuming you really need to assign a value to a variable (it could probably be avoided too, but let's go small steps first), do it the Struts way:

<s:set var="type" value="0" />
<s:if test='#session.containsKey("currentUserType")'>
    <s:set var="type" value='#session["currentUserType"]' />
</s:if>

Or one-liner

<s:set var="type" 
     value='%{#session["currentUserType"]!=null?#session["currentUserType"]:0}'

Or much better, in Action class:

public Integer getType(){
    return session.containsKey("currentUserType") 
                   ? session.get("currentUserType") 
                   : 0;
}

EDIT

I know (knew) what you are trying to achieve. I'm just telling you that there are several better alternatives. Does that JSP seem clean to you ?

For example if you have three main profiles, you can create three JSP snippets for your header, and with <s:if type="... include only the right one (with <jsp:include>, or better <s:include>, NOT with <%@ include %>).

Consider having a main-head.jsp included in all of your JSPs;

in main-head.jsp:

<s:if test="type==0">
    <s:include page="guest-head.jsp"/>
</s:if>
<s:elseif test="type==1">
    <s:include page="admin-head.jsp"/>
</s:elseif>
<s:elseif test="type==2">
    <s:include page="user-head.jsp"/>
</s:elseif>

Still ugly (this is a start), but much better.

The first part of the answer is still completely valid, but keep in mind this new part too, to improve the design of your pages.

Hi there, certain parts of the `index.jsp` turn on/off depending on the `type` (0 = guest, 1 = admin, 2 = user). Different user types see different things on the same jsp, so that is why I need to get the `type` in the jsp. Let me post the whole `index.jsp` to show what I was trying to achieve. If you can elaborate on the Action class approach after seeing the whole code, it would be much appreciated. Thanks. — k_rollo, Nov 13 '14 at 16:35
I have a follow-up question but it's regarding the Struts2 if-else-if. However, I think it may need it's own thread as it may deviate from this topic. Thanks for your response. — k_rollo, Nov 14 '14 at 02:26

Cannot get attribute from session in Struts 2

1 Answers1

EDIT