Question

I am trying to use addActionMessage() and addActionError() to pass messages and error from actions (e.g. in execute()) to the forwarded page.

In the JSP, I use:

<s:if test="hasActionMessages()">
   <s:actionmessage/>
</s:if>

to display such messages.

But no message is shown. I am wondering if anyone could give a fix on this problem, or suggest another solution. I am new to Struts and web development, and I am not sure what is a proper pattern for passing messages from actions to pages.

EDIT: action-mapping code and java code

<action name="myAddUser" class="org.any.backend.action.UserAdminAction" method="addUser">
  <result name="success" type="redirectAction">myUserAdmin</result>
  <result name="input" type="redirectAction">myUserAdmin</result>
</action>

Java code:

    public String addUser() throws Exception {
    // check duplicate
    for (User u : userList)
        if (u.getUserName().equals(userName)) {
            addActionError("A user with the same user name already exists. Choose another user name. ");
            return INPUT;
        }
    if (userName != null && !userName.isEmpty() && password != null && !password.isEmpty()) {
        User newUser = new User();
        newUser.setUserName(userName);
        newUser.setPassword(password);
        userList.add(newUser);
        addActionMessage("User " + userName + " added. ");
        return SUCCESS;
    } else {
        addActionError("User name and password cannot be empty");
        return INPUT;
    }
}

Answer 1

Your code is right.

Maybe you are using a REDIRECT-ACTION result type, or a CHAIN.
They both will lose action messages and errors, forcing you to put them in session (and clean them once displayed) for this page.

EDIT: I’m assuming that you are using the block

<s:if test="hasActionErrors()">
       <s:actionerror />
</s:if>
<s:if test="hasActionMessages()">
       <s:actionmessage/>
</s:if>

and not only the posted one, or you will never see the errors, only the messages…