Value of Value stack is changed after execute another action in Struts2

Question

I have like following jsp.I send some data via form and execute Action,

case.jsp

before action:${CasePostFormBean.subject}
<s:action var="ServletHelperAction" name="login-user-to-bean" namespace="/servlet-helper"></s:action>
after action:${CasePostFormBean.subject}

<input name="CasePostFormBean.subject" value="${CasePostFormBean.getSubject()}" form="formCasePost">

<form method="post" id="formCasePost" submit="case-create"></form>

servlethelper.jsp

<html></html>

CasePostAction.java

public class CasePostAction extends ActionSupport implements SessionAware {

    @Getter @Setter
    private CasePostFormBean casePostFormBean = new CasePostFormBean();

    @Action(value = "case-create", results = {
        @Result(location = "case.jsp")
    })
    public String register() {
        this.casePostFormBean.setSubject("success to send form");
        return SUCCESS;
    }
}
}

public class ServletHelperAction extends ActionSupport implements SessionAware  {

    // Beans
    @Getter @Setter
    private UserParamsBean userParamsBean = new UserParamsBean();

    @Action(value = "login-user-to-bean", results = {
        @Result(location = "servlethelper.jsp")
    })
    public String loginUserToBean() {
        final MstUserModel mstUserModel = new MstUserModel(this.dbManager.getSqlSession());

        if (this.session.get("userParamsBean.userCode") != null) {
            this.userParamsBean.setUserCode(this.session.get("userParamsBean.userCode").toString());

            Map<String, Object> loginUser = mstUserModel.selectUserOne(1, this.userParamsBean.getUserCode()).get(0);
            this.userParamsBean.setUserName(loginUser.get("name").toString());
        }
        return SUCCESS;
    }
}

After input input value and after button submitted, like following was shown.

before action: success to send form
after action: input value

Out put is like follows, When I execute another action via <s:action> the value stack seems to be changed. Seems that after <s:action> these sent data was recaptured by value stack.

My desired result is like

before action: success to send form
after action: success to send form

What is the root cause of this?

The value stack is local to the action. It seems that you are using objects from different scope. It can't be figured out because you didn't post all necessary details. — Roman C, Dec 16 '22 at 12:31
It's not clear why you expect this to do what you want. `this` is the action being called; it has its own `casePostFormBean`. The pattern seems incorrect anyway--what problem are you trying to solve? — Dave Newton, Dec 16 '22 at 14:49
I edited my question, as I am novice to this concept,, I would like to figure out `Object scope`.. `casePostFormBean` has different scopes ? thanks ! — Heisenberg, Dec 19 '22 at 01:23

score 1 · Accepted Answer · answered Dec 26 '22 at 11:29

If you set some bean to the action object, then it belongs to it until you reference it someare else, i.e. a session map. Since you have to implement a SessionAware interface on CasePostAction. Then you put CasePostFormBean into the session map. In this way the scope of the object will be a session scope until you remove it from the session or invalidate a session map.

In the JSP you use EL expression to search for the CasePostFormBean. Currently you keep it in the action bean and a scope belongs to the action scope.

The action scope is similar to the request if you don't instantiate other actions in the request like <s:action>. Each action has its own action scope and therefore a ValueStack.

Change the code

public class CasePostAction extends ActionSupport implements SessionAware {

    @Getter @Setter
    private CasePostFormBean casePostFormBean = new CasePostFormBean();

    @Getter @Setter
    private Map<String, Object> session;

    @Action(value = "case-create", results = {
        @Result(location = "case.jsp")
    })
    public String register() {
        
this.casePostFormBean.setSubject("success to send form");
        session.put("casePostFormBean", casePostFormBean);
        return SUCCESS;
    }
}
}

When a result is executed you should reference this object directly from the session.

before action:<s:property value="%{#session.casePostFormBean.subject}"/>
<s:action var="ServletHelperAction" name="login-user-to-bean" namespace="/servlet-helper"></s:action>
after action:<s:property value="%{#session.casePostFormBean.subject}"/>

Value of Value stack is changed after execute another action in Struts2

1 Answers1