了解动作阶段和渲染阶段的执行

本文介绍了了解动作阶段和渲染阶段的执行的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在使用Liferay 6进行门户开发.

通过阅读《 Liferay开发人员指南》 ，作者解释说: Portlet执行的两个阶段

行动阶段

渲染阶段

public class DateTimePortlet extends GenericPortlet { public void doView(RenderRequest req, RenderResponse res) throws IOException, PortletException { Object actionAttribute = req.getAttribute("datetime"); res.getWriter().println("Date Time:" + (actionAttribute != null ? actionAttribute :"Unavailable")); res.getWriter().println("<BR/>"); PortletURL u = res.createActionURL(); res.getWriter().println("<A href=" + u + ">Trigger an action."); res.getWriter().close(); } public void processAction(ActionRequest req, ActionResponse res) throws PortletException { req.setAttribute("datetime",new Date()); } }

我的理解是doView方法被称为"渲染阶段"，而processAction方法被称为"动作阶段".

如果页面上显示5个portlet，则每次页面刷新都会执行渲染阶段"(即doView方法中的代码).

请告诉我我是否正确.

解决方案

是的，正确的:最大. 1个Portlet处理每个请求的操作，但是页面上的所有Portlet都将运行一个渲染请求(除非输出被缓存，但让我们放下这个相当高级的内容)

仅完成渲染后，对请求的处理也可能为0(这是通常在portlet上执行的最常见的操作.在此阶段，您必须(并且不能)更改任何状态.)

在执行操作之后，可以触发事件阶段(请参阅Port-Portlet通信，IPC)，该阶段可以在任意数量的Portlet上执行.

如果您不希望重新加载整个页面，则必须进入资源阶段，在此阶段您可以处理AJAX调用并提供各种不同的资源，而Portlet所要使用的常规页面片段除外.服务.

I am using Liferay 6 for the Portal Development .

By going through Liferay Developer Guide the author explains that there are Two phases of Portlet Execution

Action Phase

Render Phase

public class DateTimePortlet extends GenericPortlet { public void doView(RenderRequest req, RenderResponse res) throws IOException, PortletException { Object actionAttribute = req.getAttribute("datetime"); res.getWriter().println("Date Time:" + (actionAttribute != null ? actionAttribute :"Unavailable")); res.getWriter().println("<BR/>"); PortletURL u = res.createActionURL(); res.getWriter().println("<A href=" + u + ">Trigger an action."); res.getWriter().close(); } public void processAction(ActionRequest req, ActionResponse res) throws PortletException { req.setAttribute("datetime",new Date()); } }

My understanding is that the doView method is known as "Render Phase" and the processAction Method is known as "Action Phase".

And if there are 5 portlets displayed on a page, the "Render Phase" (That is the code inside the doView Method) is executed for every Page refresh.

Please let me know if i am correct.

解决方案

Yes, correct: There's max. 1 portlet handling an action per request, but all of the portlets on the page will have a render request running (unless the output is cached, but let's put aside this rather advanced stuff)

There can also be 0 action handling on a request, when just rendering is done (this is the most common operation typically executed on a portlet. You must (and can) not change any state in this phase.).

Following an Action, the event phase can be triggered (see Inter-Portlet-Communication, IPC) that can be executed on any number of portlets.

If you don't want a full page reload, you'll have to look into the resource-phase where you can handle AJAX calls and serve all kinds of different resources other than the usual page fragments that a portlet is meant to serve.