通过struts.xml配置设置栈顶值

　　第一种方式：(不建议使用)
　　ActionContext.getContext().getValueStack().push(obj);
　　
　　第二种方式：
配置struts.xml中配置自定义拦截器如下：
　　<interceptors>
	<interceptor-stack name="mystack">
		<interceptor-ref name="defaultStack">
			<param name="modelDriven.refreshModelBeforeResult">true</param>
		</interceptor-ref>
	</interceptor-stack>
    </interceptors>

　　<default-interceptor-ref name="mystack" />
　　
　　
　　
　　

查看[ModelDrivenInterceptor]源码：



public class ModelDrivenInterceptor extends AbstractInterceptor {

    protected boolean refreshModelBeforeResult = false;

    public void setRefreshModelBeforeResult(boolean val) {
        this.refreshModelBeforeResult = val;
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        Object action = invocation.getAction();

        if (action instanceof ModelDriven) {
            ModelDriven modelDriven = (ModelDriven) action;
            ValueStack stack = invocation.getStack();
            Object model = modelDriven.getModel();
            if (model !=  null) {
            	stack.push(model);
            }
            if (refreshModelBeforeResult) {
                invocation.addPreResultListener(new RefreshModelBeforeResult(modelDriven, model));
            }
        }
        return invocation.invoke();
    }

    /**
     * Refreshes the model instance on the value stack, if it has changed
     */
    protected static class RefreshModelBeforeResult implements PreResultListener {
        private Object originalModel = null;
        protected ModelDriven action;


        public RefreshModelBeforeResult(ModelDriven action, Object model) {
            this.originalModel = model;
            this.action = action;
        }

        public void beforeResult(ActionInvocation invocation, String resultCode) {
            ValueStack stack = invocation.getStack();
            CompoundRoot root = stack.getRoot();

            boolean needsRefresh = true;
            Object newModel = action.getModel();

            // Check to see if the new model instance is already on the stack
            for (Object item : root) {
                if (item.equals(newModel)) {
                    needsRefresh = false;
                }
            }

            // Add the new model on the stack
            if (needsRefresh) {

                // Clear off the old model instance
                if (originalModel != null) {
                    root.remove(originalModel);
                }
                if (newModel != null) {
                    stack.push(newModel);
                }
            }
        }
    }
}