Java Struts 1：从动作转向动作。通过ActionForms传递数据

Question

We've been trying to redirect from one action to another, hoping that data would be passed between corresponding ActionForm beans. The first action receives a request from the browser, prints a data field, and forwards it to another action, which prints the same field and redirects to a JSP.

The problem is that ActionTo is printing an incorrect value - its commonInt has a default value of 0 , while we expect 35 .

Here is a representing example:

public class ActionFrom extends DispatchableAction{

    public ActionForward send(ActionMapping mapping, ActionForm form, HttpServletRequest request,HttpServletResponse response){
        FormA formA = (FormA)form;

        formA.commonInt = 35;
        System.out.println("sent: "+formA.commonInt);
        return mapping.findForward("send");
    }
}

public class ActionTo extends DispatchableAction{

    public ActionForward recv(ActionMapping mapping, ActionForm form, HttpServletRequest request,HttpServletResponse response){
        FormB formB = (FormB)form;

        System.out.println("recv= "+formB.commonInt);

        return mapping.findForward("send");
    }
}

And actionForms are:

public class FormA extends ActionForm {
    public int intA;
    public int commonInt;
}

public class FormB extends ActionForm{
    public int intB;
    public int commonInt;
}

Mappings:

<action path="/from" type="EXPERIMENT.ActionFrom" name="formA" scope="request"
      input="something.jsp" parameter="dispatch" unknown="false" validate="false">
 <forward  name="send" path="/to.do?dispatch=recv" redirect="false"/>
</action>

 <action path="/to" type="EXPERIMENT.ActionTo" name="formB"  scope="request"
      input="something.jsp" parameter="dispatch" unknown="false" validate="false">
      <forward name="send" path="/login.do"  redirect="false"/>
 </action>

Is there a way to accomplish this? Or both forms should be the same?

The workaround we tried was to pass things through request, but it can get large and messy.

Answer 1

Tom, using you solution and combining with ActionRedirect , suggested by Vincent Ramdhanie, I got what you wanted too.

The code is simple as that and it allow you to have separated Forms for each Action.

ActionRedirect redirect = new ActionRedirect(mapping.findForward("send"));
redirect.addParameter("commonInt", formA.getCommonInt());
return redirect;

formB.setCommonInt(request.getParameter("commonInt"));

This endend up saving my day and helping me not to have the effort to change that directly in the JSP, what would be awful.

Answer 2

The way to accomplish this is to use the same actionform for both actions. Is there a specific reason why you need two different actionforms? If not try modifying the second action mapping to name="formA" and the action itself to use FormA rather than FormB.

Answer 3

Sounds like this could get messy, I'd keep this simple and use the ActionForm only to store Request data.

public class FormA extends ActionForm {
    public int intA;
    public int commonInt;
}

Once the Request has been submitted take the data out of the ActionForm and stuff it into the session somewhere, either directly, or into a data holder within the session to maintain this kind of information.

public class ActionTo extends DispatchableAction {
  public ActionForward recv(ActionMapping mapping, ActionForm form, HttpServletRequest request,HttpServletResponse response) {
    FormA form = (FormA)form;

    DataHolder dataHolder = request.getSession().getAttribute("dataHolder");
    dataHolder.setCommonInt(commonInt);
    dataHolder.setIntA(intA);

    return mapping.findForward("send");
  }
}

Ideally, if you're not heavily invested in Struts 1 I'd take a look at Struts 2.