filterconfig struts2执行流程(10)

简单点说就是：这个静态资源在项目中存在就返回，不存在就放行，交给其他的过滤器处理。

那就调用ExecuteOperations的executeAction方法去执行这个Action，源码如下：

public void executeAction(HttpServletRequest request, HttpServletResponse response, ActionMapping mapping) throws ServletException {
  dispatcher.serviceAction(request, response, servletContext, mapping);
}

它又调用了Dispatcher的serviceAction方法，源码如下：

public void serviceAction(HttpServletRequest request, HttpServletResponse response, ServletContext context,
                      ActionMapping mapping) throws ServletException {

    Map<String, Object> extraContext = createContextMap(request, response, mapping, context);

    // If there was a previous value stack, then create a new copy and pass it in to be used by the new Action
    ValueStack stack = (ValueStack) request.getAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY);
    boolean nullStack = stack == null;
    if (nullStack) {
        ActionContext ctx = ActionContext.getContext();
        if (ctx != null) {
            stack = ctx.getValueStack();
        }
    }
    if (stack != null) {
        extraContext.put(ActionContext.VALUE_STACK, valueStackFactory.createValueStack(stack));
    }

    String timerKey = "Handling request from Dispatcher";
    try {
        UtilTimerStack.push(timerKey);
        // 获取ActionMapping中的namespace，name，method
        String namespace = mapping.getNamespace();
        String name = mapping.getName();
        String method = mapping.getMethod();

        Configuration config = configurationManager.getConfiguration();
        // 创建ActionProxy代理
        ActionProxy proxy = config.getContainer().getInstance(ActionProxyFactory.class).createActionProxy(
                namespace, name, method, extraContext, true, false);

        request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, proxy.getInvocation().getStack());

        // if the ActionMapping says to go straight to a result, do it!
        // 如果mapping中有结果集，那么就去执行结果集
        if (mapping.getResult() != null) {
            Result result = mapping.getResult();
            result.execute(proxy.getInvocation());
        } else {
            // 代理开始执行
            proxy.execute();
        }

        // If there was a previous value stack then set it back onto the request
        // 之前已经有值栈了，就把它放入当前request域里面
        if (!nullStack) {
            request.setAttribute(ServletActionContext.STRUTS_VALUESTACK_KEY, stack);
        }
    } catch (ConfigurationException e) {
        logConfigurationException(request, e);
        sendError(request, response, context, HttpServletResponse.SC_NOT_FOUND, e);
    } catch (Exception e) {
        if (handleException || devMode) {
            sendError(request, response, context, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
        } else {
            throw new ServletException(e);
        }
    } finally {
        UtilTimerStack.pop(timerKey);
    }
}

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