1.功能目的:
这个系列是想通过DWR最终实现服务器到客户端的推送,形象描述类似于在页面不刷新的前提下,页面会接收到服务器推送给当前用户的消息,以气泡形式展现。
2.为何使用DWR:
这里可以参考我博客中的其他文章,很大部门摘自于网络。十分感谢这些具备分享精神的同仁们。我这里就不详细阐述了。
3.DWR学习的一些相关资料:
官网地址:
http://directwebremoting.org/dwr/
其实针对于DWR的学习,官网已经给了非常详尽的资料了。在线demo,简单的部署教程以及API等等非常详细了。
学习demo下载地址:http://download.csdn.net/download/techbirds_bao/5505799
4.helloword的dwr基础入门
目录结构:
步骤
1.jar包导入
2.web.xml配置
- <web-app id="dwr">
- <display-name>DWR (Direct Web Remoting)</display-name>
- <description>A Simple Demo DWR</description>
- <servlet>
- <servlet-name>dwr-invoker</servlet-name>
- <display-name>DWR Servlet</display-name>
- <description>Direct Web Remoter Servlet</description>
- <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
- <!-- This should NEVER be present in live -->
- <init-param>
- <param-name>debug</param-name>
- <param-value>true</param-value>
- </init-param>
- <!-- Remove this unless you want to use active reverse ajax -->
- <init-param>
- <param-name>activeReverseAjaxEnabled</param-name>
- <param-value>true</param-value>
- </init-param>
- <!-- By default DWR creates application scope objects when they are first
- used. This creates them when the app-server is started -->
- <init-param>
- <param-name>initApplicationScopeCreatorsAtStartup</param-name>
- <param-value>true</param-value>
- </init-param>
- <!-- This enables full streaming mode. It's probably better to leave this
- out if you are running across the internet -->
- <init-param>
- <param-name>maxWaitAfterWrite</param-name>
- <param-value>-1</param-value>
- </init-param>
- <!--
- For more information on these parameters,see:
- - http://getahead.org/dwr/server/servlet
- - http://getahead.org/dwr/reverse-ajax/configuration
- -->
- <load-on-startup>1</load-on-startup>
- </servlet>
- <servlet-mapping>
- <servlet-name>dwr-invoker</servlet-name>
- <url-pattern>/dwr/*</url-pattern>
- </servlet-mapping>
- </web-app>
3.dwr.xml配置
- <?xml version="1.0" encoding="UTF-8"?>
- <!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://getahead.org/dwr/dwr20.dtd">
- <dwr>
- <allow>
- <!-- base -->
- <create creator="new" javascript="Say" scope="application">
- <param name="class" value="org.getahead.dwrdemo.base.Say"/>
- </create>
- </allow>
- </dwr>
4.dwr后台调用java类编写
- package org.getahead.dwrdemo.base;
- public class Say {
- public String hello(){
- return "hello";
- }
- public String world(){
- return "world";
- }
- }
5.页面调用
- <%@ page language="java" contentType="text/html; charset=UTF-8"
- pageEncoding="UTF-8"%>
- <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
- <html>
- <head>
- <Meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
- <title>dwr基础使用</title>
- <script type='text/javascript' src='../dwr/engine.js'> </script>
- <script type='text/javascript' src='../dwr/interface/Say.js'> </script>
- <script type='text/javascript' src='../dwr/util.js'> </script>
- </head>
- <body onload="dwr.engine.setActiveReverseAjax(true);">
- <input type="button" value="say hello" onclick="sayHello();"/>
- <br/>
- <input type="button" value="say world" onclick="sayWorld();"/>
- </body>
- <script type="text/javascript">
- function sayHello(){
- Say.hello(function(data){
- alert(data);
- });
- }
- function sayWorld(){
- Say.world(function(data){
- alert(data);
- });
- }
- </script>
- </html>