Redirect to another action in an interceptor in struts 2
- by user292662
I am currently in the process of learning Struts 2 and I am currently building a simple application where unverified users are redirected to a login form.
I have a login form and action functional which takes the users credentials, verifies them and stores a User object in the session however I am now trying to prevent access to pages before the login has taken place and I am trying to do this with an interceptor.
My problem is that I have written an interceptor that checks whether the User object has been saved in the session but if it has not I want to redirect to the login page and can't find any way of doing this without bypassing struts and using the HttpServletResponse.sendRedirect method 
Configuration: 
<package name="mypackage" extends="struts-default" namespace="/admin">
    <interceptors>
        <interceptor name="login" class="my.LoginInterceptor" />
    </interceptors>
    <default-interceptor-ref name="login"/>
    <action name="login" class="my.LoginAction">
        <result name="input">/admin/login.jsp</result>
        <result name="success" type="redirect">/admin</result>
    </action>
    <action name="private" class="my.PrivateAction">
        <result>/admin/private.jsp</result>
    </action>
</package>
The interceptor code:
@Override
public String intercept(ActionInvocation inv) throws Exception {
    Map<String, Object> session = inv.getInvocationContext().getSession();
    Object user = session.get("user");
    if(user == null) {
                      // redirect to the 'login' action here            
    }
    else {
        return inv.invoke();
    }
}