问题描述

将应用程序从 Struts 1 迁移到 Struts 2 时

While migrating the application from Struts 1 to Struts 2

在某些地方，根据请求参数，相同的操作类已用于不同类型的视图.

In some of the places, the same action class has been used for different type of views, based on the request params.

例如:如果 createType 为 1 表示需要附加一个参数，或者如果 createType 为 2 表示需要附加一些额外的参数，就像我需要的那样使用 ActionForward 将动态参数传递给其他操作.

For example: if the createType is 1 means need to append one param or if the createType is 2 means need to append some more extra params, like that I need to pass dynamic params to some other action using ActionForward.

struts-config.xml:

<action path="/CommonAction" type="com.example.CommonAction" scope="request">
    <forward name="viewAction" path = "/ViewAction.do"/>
</action>

动作类:

public class CreateAction extends Action
{
    public ActionForward execute(ActionMapping m, ActionForm f, HttpServletRequest req, HttpServletResponse res) throws ServletException, Exception
    {
            String actionPath = m.findForward("viewAction").getPath();
            String createType = req.getParameter("createType");
            String params = "&action=view";
            if("1".equals(createType)){
               params = params + "&from=list";
            }else if("2".equals(createType)){
               params = params + "&from=detail&someParam=someValue";
            }//,etc..
            String actionUrl = actionPath+"?"+params;
            return new ActionForward(actionUrl);
    }
}

但是，我不能在 Struts 2 中做同样的事情.是否有可能在 Struts 2 中使用动态参数更改 ActionForward ?

But, I not able to do the same thing in Struts 2. Is there any possibilities to change ActionForward with dynamic params in Struts 2 ?

推荐答案

您可以使用带有 result 的动态参数，请参阅 动态结果配置.

You could use a dynamic parameters with a result, see the dynamic result configuration.

在动作中你应该为参数写一个getter

In the action you should write a getter for the patrameter

private String actionUrl;

public String getActionUrl() {
    return actionUrl;
}

并配置结果

<action name="create" class="CreateAction">
    <result type="redirect">${actionUrl}</result>
</action>

所以，常识是像这样重写代码

So, the common sense would be rewrite the code like

public class CreateAction extends ActionSupport
{

    private String actionUrl;

    public String getActionUrl() {
        return actionUrl;
    }

    @Override
    public String execute() throws Exception
    {
            String actionPath = "/view";
            String createType = req.getParameter("createType");
            String params = "&action=view";
            if("1".equals(createType)){
               params = params + "&from=list";
            }else if("2".equals(createType)){
               params = params + "&from=detail&someParam=someValue";
            }//,etc..
            actionUrl = actionPath+"?"+params;
            return SUCCESS;
    }
}

如果您需要更好的方法从操作映射创建 url，您可以查看 这个答案.

If you need a better way to create the urls from action mapping, you could look at this answer.

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