Struts2 ActionContext和ValueStack?

问题描述

我的问题是:

1. 在Struts2中，每个动作对象是否都有自己对应的ActionContext和ValueStack?

换句话说，对于每个新请求，都会创建一个新的操作对象.这是否意味着每次创建一个新的动作对象时，也会同时创建一个新的ActionContext和ValueStack?

In other words, for every new request a new action object is created. Does this mean every time a new action object is created, a new ActionContext and ValueStack also get created?

1. 考虑这种情况:

Action1 ------ 1st req -------> view.jsp ------ 2nd req ---------> action2.

Action1------1st req------->view.jsp------2nd req--------->action2.

因此，当请求action1时，将创建action1的新对象以及相应的ActionContext和ValueStack.

So when a request comes for action1 a new object of action1 and corresponding ActionContext and ValueStack will get created.

在view.jsp中(单击超链接时)，有一个新的请求将请求action2.

From view.jsp (upon clicking hyperlink) a new request goes for action2.

这是否意味着先前的ActionContext和ValueStack(与action1相关)被销毁，而新的ActionContext和ValueStack(对于action2)则被创建?

Does this mean that previous ActionContext and ValueStack (related to action1) gets destroyed and a new ActionContext and ValueStack (for action2) gets created?

1. 假设我将某些内容存储在view.jsp中的(动作1的)ActionContext中，然后单击动作2的超链接(来自view.jsp)，那么该数据和(动作1的)ActionContext是否会丢失?

1. Suppose I store something in ActionContext (of action1) in view.jsp and then click on hyperlink for action2 (from view.jsp), will that data along with the ActionContext (of action1) get lost?

推荐答案

1. 是

2. 是，在执行动作后将进行清理.

1. Yes

2. Yes after action execution clean up will be done.

//SourceCode from StrutsPrepareAndExecuteFilter.

//Cleans up a request of thread locals

public void cleanupRequest(HttpServletRequest request) {

  Integer counterVal = (Integer) request.getAttribute(CLEANUP_RECURSION_COUNTER);
  if (counterVal != null) {
      counterVal -= 1;
      request.setAttribute(CLEANUP_RECURSION_COUNTER, counterVal);
      if (counterVal > 0 ) {
          if (log.isDebugEnabled()) {
              log.debug("skipping cleanup counter="+counterVal);
          }
          return;
      }
  }

  // always clean up the thread request, even if an action hasn't been executed
  ActionContext.setContext(null);
  Dispatcher.setInstance(null);
}

3.是的，如果您希望在下一个操作中使用该数据，请使用链(不建议使用).

3.Yes, If you want that data available in the next action use chain(not suggestible).

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