计算机毕业设计 译文

1、下一代网络技术在以前，互联网只是一堆静态的网页。而今天互联网与我们的生活联系很充 分，这要归功于所谓的Web 2.0技术集的使用。现在这种技术已经很受欢迎了， 甚至连企业都很想用它们。在本文中，我们来探讨这些技术，以及它们如何能激 励下一代企业门户的发展。另外，我们来设想一下Web 2.0技术的未来前景。要了解和欣赏下一代网络技术，重要的是要了解上个技术年代提供的技术基 础。长期以来，网站只不过是一个由一堆网页形成用来给大家一起点击和浏览。 虽然经过事实证明这是了不起的信息来源，但是也有很多限制。举个例说：人们 不能相互影响，这只是一次在一个页面上的浏览经历。如果两个人在同一个网站 浏览，它们

2、也没有办法知道对方的存在。如果你想修改网页或其中的一部分，那 么你必须熟悉HTML编码。而且你必须修改已经完成的网页。有没有办法只拿出 它的一部分出来修改呢。在以前的一段时间里，网站就想雨后春笋般的出现和成 长。局势变成如果要变得消息联通，那么它必须要拥有一个网站。有这么多的网 站由一堆静态的页面组成，我们在互联网上的生活变的相当乏味。所以我们要打 破这种单调的网上生活。关于Web 2.0的事情。它没有在一夜之间涌现。事实上，它已经存在了许多 年，现在逐渐的进入我们的生活，它包括许多技术，这些技术我们都已经听过如 JavaScript，XML 的，ASP.Net 和 PHP / Perl，My

3、SQL 和等，这些是处理网络数 据的不同方式。软件公司开始使用这些和其他类似的技术到应用程序当中。我们 都听过内联网和知识管理解决方案和在线客户关系管理等套件，这些都是以某种 方式来实现对建立下一代网络技术的。不幸的是，它们在过去都被忽视了。开始慢慢的有些人提出这些技术运用在实际创造中使用，这些技术开始慢慢 的被人们注意。我们大家都听说过博客，维基百科，YouTube以及Flickr，等等， 这些都转化为一个平台的，而不是静态信息来源网络。博客是让普通用户在网上 发帖，通过帖子把别人不知道的事用HTML发表出来。维基的思想是让用户可以 在线编辑发表意见。YouTube和Flickr不需要介绍。

4、他们已经成为社会网络世 界的火炬手。当有人说起Web 2.0，它们的名字总是被人们第一个想起。所用通 过申请得到网上新的身份的用户就不仅可以访问数据，还可以参与到数据的增加 中。在浏览器中的应用中，用户可以自由的修改实时内容，多个用户之间也可以 相互交流。用户可以从其他的网站中得到内容而积累的内容可以形成自己的网 站，现在创办基于Web的桌面，观看视频Web浏览器，博客，所有这些现在已经 实现，在网络技术的发展要像它表示感谢。Web 2.0的出现，也为企业提供了一些商机。随着应用网站如维基，博客等 的出现能够简易的将信息聚合在一起，就可以使它们的解决方案更加的有互动 性。为用户提供有用的信息。

5、当提及Web 2.0技术成功的背后支持，AJAX是出 现的第一个名称。因此，让它引路，让我们看看一些其他的塑造了新的网络的基 本技术。AJAX今天，每当第二个互联网用户出现就有一个Gmail账户。当我们要上传和分 享在网络上的图片的时候，大多数人都会使用Flickr。当我们在一个地区旅游 的时候，我们一般会使用谷歌地图来定位。当然，你必须认识到，一个全新的动 态Web应用程序正在出现新品种。这些应用程序大多是外观和风格类似的桌面应 用程序。AJAX （异步JavaScript和XML）是一种技术。它使网页交换服务器与 少量的数据反应，在背后，使整个网页并不需要重新加载每次用户发出请求。这 样有

6、助于改善网站总体的交互性，速度性，功能和网页的可用性。JavaScript 是主要的编程语言，其中的AJAX函数用来被调用的和使用XML的异步检索到的 数据的格式和保存。作为一种跨平台的技术，使之可以在不同的操作系统，计算 机体系结构和Web浏览器中使用。Web应用程序总是比桌面应用程序有更多的实 惠，他们很容易使用，安装和发展，但缺乏交互性。恰恰AJAX的解决了这个问 题。AJAX结合了多种技术，它们都有独自蓬勃发展的权利。以一种强大的方式结 合在一起。我们用XHTML和CSS组成一种标准的演示方式。动态显示和交互可以 合并使用文档对象模型。数据互换和操纵，主要是XML和XSLT工作。异步数

7、据检索在XMLHttpRequest的JavaScript的帮助下完成，在客户端生成检 索结果，结合每个事件实现动态显示与信息交互。XMLHttpRequest对象一直是 AJAX成功实现资料显示和相互作用的关键。因为它使服务器的异步数据交换得 以实现。一个企业也可以实现在其门户网站的AJAX的应用。有AJAX你可以建立丰富 的应用和动态的内容，还可以提供简单的功能，例如拖放和自动完成。AJAX是 一个框架结构和得到现在被人们喜爱的Java和.NET的支持。在微软的ASP 2.0 介绍后，与Web 2.0兼容的Web应用程序开发这件事情就变得简单了很多。在某 种程度上，你甚至不必是一个AJAX

8、的专家就可以很好的使用它。有ASP 2.0， Web开发人员就可以让工作中的一部分与服务器通信独立.mash ups这些增值服务是由第三方提供轻量级的工具，为Web应用程序的综合服务。 主要是mash-ups工具是源自与第三方通过一个公共接口或API得到的内容。例 如，在你的个人主页中一个小模块展示本地的天气预测，在另外的小模块中显示 您的新闻标题，这是以混合搭配的形式展开的行动。一个mash-ups的应用程序一般包括三个不同的参与者，艮即API/内容提供 者，mash-ups的位置和客户端浏览器界面。API /内容提供商提供内容来源。它们以网络协议形式通过API提供内容。例如提供的REST的

9、检索内容，Web 服务或RSS/Atom供稿。有一些网站，不提供内容检索的设备。因此由mash-up技术来提取这些网站 的内容。屏幕抓取是一个方法，用一个工具尝试提取内容提供商，尝试把提供商 的页面格式化为XML数据检索的内容，难后发送一个作为HTTP请求的响应返回 的信息。在另一方面，其中一个mash - up网站提供它的逻辑地址。mash-ups 网站同样可以支持对传统的Web应用服务器端动态内容生成技术，如 Java servlet的和PHP或ASP。最后，mash - up的应用程序呈现在客户的浏览器界 面，并在实际中与用户交互发生。有趣的是，这些mash - ups为企业开辟了新的途

10、径，就因为它呈现出的可 互操作性。例如：一个SAP ERP与Java应用程序或一个PHP的网站通信，并提 出了统一的结果给用户。mash - ups的内容来源也可以是不同的Web服务器。 让mash - ups技术进入企业的内部网，这是一件意义重大的事。这将提供一个 平台，可以从不同的应用程序来访问企业的网站。作为门户网站将使用Web浏览 器，要访问的时候就不需要安装客户端了，这样可以适用于不同的应用环境，从 而使员工能够灵活的从不同的地点使用。企业只需要在网络上拥有自己的Web 浏览器界面。Web feed它使用特定的数据格式向订阅的用户提供更新的内容。代理商提供一个Web feed，其内容

11、满足客户的订阅。Web feed的内容通过网络聚合集中在一个模块 里。这个模块可以是一个客户端软件或是一个基于Web的服务，这种模块就像博 客中的一块内容，比如新闻等独自在一个模块。Web feed的功能简单的说就是从Web浏览器中拖一个链接到这个模块当中。 代理商提供内容，在其网站上发表满足客户的订阅需求。并通过一个模块在它们 的电脑上聚合这些内容。再聚合查询在服务器上与这些有关的新的内容，然后把 新的内容用说明的方式显示出来，或者下载到客户端浏览器。Web feeds被设计成机器可读而不是人可读，因此它们可以被用来自动的传 递信息从一个网站到另一个网站在没有人的操纵下。它的两个主要的Web

12、 feed 格式是RSS和Atom。RSS：，当被用于提供者和聚合者用于网站的摘要和聚合的时候，它就是一中 基于XML的协议。Rss以一种简单的XML文件形式被这些网站的所有者保留和自 动更新，还可以用rss阅读软件接收和和阅读。Rss是一种基于XML的文件有一 个全球标准RSS 2.0格式标记主要网站和为提供项目设置标签，代表已发表的链 接/网站上的更新。每一个这样的项目标签包括一个标题，代表该项目的简短描 述和对XML格式的全文链接。在RSS阅读器软件下载该XML文件并分析其形成的 HTML，就获得了用户在浏览器中的超链接的形式的显示数据，并返回原来的网站。Atom:（ATOM是一种订阅网

13、志的格式）有两种标准是：一种基于XML的文 档格式以及基于HTTP的创建和更新Web资源的协议。Atom的发展是弥补了 RSS 互动性的不足和借鉴了各种版本RSS的使用经验。尽管在功能上RSS和Atom是 一些类似，它与RSS相比来讲，有更大的弹性，使开发应用程序开发更容易。RSS可能也包含纯文本或者是脱离有效的HTML的文件。现在还没有办法说 明这两种提供。与此相反的是Atom用一个明确的标记有效的文件。因此，更多 的有效类型文件例如纯文本，转义的HTML和XHTML，XML的Base64编码的二进 制文件可以在Atom中和被提及的第三方内容同时使用。如文件，视频和音频流 也可以提出和使用。

14、RSS和Atom还有一个不同的是：Atom包括XML模式，而RSS 没有。网络订阅源对任何企业都是有用的，如果他们计划纳入其门户的解决方案。 它可以很好的用于在显示企业数据，以及最新的软件建设，网络的正常运行，即 将举行的公司会议和其他项目中。企业2.0之路协作和资源共享已经表明了，企业运用Web 2.0的前景，企业可以从这两点 上获益。博客和维基是两个协作技术，企业可以把它们融入他们的门户解决方案。 添加博客，企业门户将增加人类的互相联系和操作促进和客户或管理雇员的关 系。同样，一个中心信息库可以在维基的帮助下创建。正如我们所讲的mash - ups和Web feed它们可以有效的在企业使用

15、窗口。 通过Web feed，员工可以保持掌握最新的企业应用中存储的数据资料mash - ups 在另一方面，提供丰富的用户界面，使用户更容易找到并使用信息，他可以按需 要分配任务和角色。很多软件作为服务模式的应用程序正在开发中，作为Web应用程序使用。目 前，企业已经使用这种模式的软件在客户关系管理，人力资源，会计和电子邮件 领域。各部门可以根据需要申请并安装这些软件并通过网络来访问。现在，这些 应用程序可以提供在互联网上的服务可以按要求在客户机上执行Web浏览器，不 需要在个别电脑上安装应用程序。在使用的是他们的门户，使员工可以借助这些 标签通过Internet远程访问应用程序，这些标签工

16、具构成了门户网站使其用户 可以使用这些标签来定义它们的公共数据库的内容。以便随后其他员工可以用这 些标签来以及它们自己增加改善搜索的标签来访问这些文件。这种新方法可以为企业带来新的业务渠道，将帮助他们增加员工和客户以及 合作伙伴之间的互动性，这对任何企业增长的都是有帮助的。Web 3.0的难道未来？当我们广泛谈论Web 2.0技术以及一个企业如何能够从中受益时，有些人已 经在一个更新的Web版本会谈的Web 3.0，也被称为，语义网。我们的目标是 使计算机能够理解信息和进行繁复的任务，如寻找，分享，结合网上的信息。随 着Web 3.0的，网上的内容虽然将不局限于只让人类理解的格式，但它有可能超

17、 越为一种形式：软件代理可以阅读，理解，从而使机器使用它们查找，共享和整 合更多的信息，这样更方便于我们。它是从蒂姆伯纳斯-李的构想中得到的 信息和知识的数据交换的网站普遍的媒介。一些关键技术，最终构成Web 3.0的技术可能会是RDF （资源描述框架）， 用一种简单的语言来表达数据模型和它们的关系。OWL （Web本体语言）是另一 种构成Web 3.0的技术。它增加了更多的描述属性和类的词汇，以及介绍了阶级 之间的关系。XML是显然和上述两种技术一起就形成了 Web3.0的主流技术。这还有些时 间才能看到它的到来。但是，这将对的桌面应用程序产生威胁。这只是个时间问 题。至此，让我们拭目以待。

18、From ： HYPERLINK /content/search/showarticle.asp?artid=99624 /content/search/showarticle.asp?artid=99624Web Technologies:Enter the NextGone are the days when Internet was only a bunch of static webs. Today, its a live and happening place, full of interactivity, thanks to a set of technologies collec

19、tively known as Web 2.0. Its become so popular that now, even enterprises want to use them. In this story, we explore these technonolgies, and how they can power next-generation enterprise portals. Plus, we take a peek into the future of Web 2.0In order to understand and appreciate the next generati

20、on of web technologies, its important to understand what the current generation has to offer. For a long time, websites were nothing but a bunch of web pages put together for people to click and browse. While it proved to be a terrific source of information, there were many limitations in it. For on

21、e, people couldnt interact on it. There was just one sea of pages to go through. If two people were browsing the same site, they had no way of knowing that. If you wanted to modify a web page or a part of it, then you had to be familiar with HTML coding. Plus, you had to modify the complete web page

22、. There was no way to change parts of it. Over a period of time, websites started springing up like mushrooms on a rotting log. The situation became that if it moves, then it must have a website. With so many websites offering the same set of static pages, life became rather boring on the Internet.

23、Something was needed to break this monotony.That something was web 2.0. It didnt spring up over night. In fact, it has been there for many years now, gradually getting into our lives. It comprises of many technologies that weve all heard of already, like JavaScript, XML, ASP.Net, PHP/Perl, MySQL, et

24、c. These gave the web a different way of dealing with data. Using these and other similar technologies, software companies started giving a web front-end to all their existing applications. Others started building applications solely for the web. Weve all heard of Intranets and knowledge management

25、solutions, online CRM packages, etc. All of these have in some way or the other contributed to building the next generation web technologies. Unfortunately, theyve all gone by relatively unnoticed.It was only after some one put these technologies to some real creative use that it started getting not

26、iced. All of us have heard of blogging, wikipedia, YouTube, Flickr, etc. All of these have converted the web into more of a platform rather than a static source of information. Blogging allowed ordinary users to post their thoughts on websites without knowing a word of HTML. Wikipedia allowed users

27、to edit what others have written online. YouTube and Flickr need no introduction. Theyve become the torch bearers for the world of social networking. Their names are the first to come to mind whenever someone says web 2.0. All these applications have given the web a new identity. Users can now, not

28、only access data, but also participate and add value to applications. Integration of applications in the browser, freedom for the user to modify content in real-time, interaction between several users, accumulation of content from other sites and feeding of the same into ones own site, having the de

29、sktop hosted on Web, watching video on a Web browser, blogging-all these are possible now, thanks to major development in the Web technologies.The emergence of Web 2.0 offers several opportunities for enterprises as well. With the integration of several applications, like Wiki, blogging, RSS feeds,

30、they can make their portal solutions much more interactive and useful for users. When ever reference to technologies behind Web 2.0 is made, AJAX is the first name that comes up. So, let us start with it and as we move on, we will cover some other essential technologies that are shaping up the new W

31、eb.AJAXToday, every second Internet user has a Gmail account, most of us use flickr to upload and share our pictures on the Web, and some of us use Google Maps to locate the area we are travelling. Surely, you must have realized that a completely new variety of dynamic Web applications are emerging.

32、 Most of these applications have looks and feel similar to that of desktop applications. AJAX (Asynchronous JavaScript and XML) is the technology that has enabled this. It makes webpages more responsive by exchanging small amounts of data with the server, behind the scene, so that the entire webpage

33、 doesnt need to reload every time the user makes a request. This helpsimprove the overall interactivity, speed, functionality and usability of the webpage. JavaScript is the main programming language wherein AJAX function calls are made and using XML the asynchronously retrieved data is formatted an

34、d kept. Being a cross-platform technology enables it to be used across different operating systems, computer architectures and Web browsers. Web apps always had more benefits than desktop apps. They were easy to use, install, and develop, but interactivity was lacking. AJAX solves that problem as we

35、ll.AJAX is a combination of several technologies each thriving in its own right, gelling together in a powerful way. We can incorporate a standard-based presentation using XHTML and CSS. Dynamic display and interaction can be incorporated using Document Object Model. Data interchanging and manipulat

36、ion is mainly the work of XML and XSLT. Data is retrieved asynchronously with the help of XMLHttpRequest and finally JavaScript, residing on client side, binds everything together and dynamically displays and interacts with the information. XMLHttpRequest object has been the key to the success of AJ

37、AX, as it enables asynchronous data exchange with servers.An enterprise can also implement AJAX in its portal. With AJAX you can build applications with rich and dynamic content, by offering simple features like drag and drop and auto-completion. AJAX is a framework model and is now relishing suppor

38、t from both Java and .NET. After the introduction of Microsofts ASP 2.0, the things have become still easy for developers working on Web 2.0 compliant Web applications. To the extent that you dont even need to be an expert in AJAX to use it. With ASP 2.0, a Web developer can compose a page out of se

39、parate working parts that communicateMash-upsThese are value added services in the form of lightweight tools provided by third parties to be integrated into a Web application. Mostly, mash-ups source the content from a third party via a public interface or API. For example, the small box on your per

40、sonal homepage showing you the local weather forecast and another box showing you news headlines, are forms of mash-up.A mash-up application would generally comprise of three different participants, namely, API/content provider, mash-up site and clients browser interface. The API/content providers a

41、re the facilitators of content being mashed (sourced). They provide the content for retrieval by making it available through APIs, which generally are in the form of Web protocols such as REST, Web services, or RSS/Atom feeds.There are some sites that do not provide facility for content retrieval, f

42、or that there are mash-up techniques to extract content from such sites. Screen scraping is a process by which a tool attempts to extract information from the content provider by attempting to parse the providers webs and formatting the retrieved content as XML data that is sent back as a response t

43、o an HTTP request. On other hand, a mash-up site is one where mash-up logic resides. The mash-ups can be implemented similarly to traditional Web applications using server-side dynamic content generation technologies, like Java servlets, PHP, or ASP. Finally, mash-up application is rendered on clien

44、ts browser interface and where actual user interaction takes place.Interestingly, these mash-ups have opened new avenues for enterprises, as it renders interoperability. For instance, an SAP ERP communicating with a Java application or a PHP website and presenting a unified result to the user. Mash-

45、ups can also be used to source contents from disparate Web services and so, it makes sense to implement mash-ups into an enterprise intranet. This will provide enterprises with a common platform, from which contents of different applications can be accessed. As portal would be using a Web browser, t

46、here would not be a need to install client-environments for different applications, and thus would provide employees the flexibility to work from different locations. They just need being on the Net and should be having a Web browser to interface.Web feedIt is a data format, which is generally used

47、to facilitate users with the content that is frequently updated. Content distributors syndicate a Web feed and require users to subscribe to it. The entire collection of Web feed is aggregated at one spot with the use of Internet aggregators. An aggregator is a client-software or Web based service t

48、hat aggregates syndicated Web content like blogs, news headlines etc, at a single location.The functionality of Web feed is, as simple as, dragging a link from the Web browser to the aggregator. The content provider publishes a feed-link on its website and the end users subscribe to it, via an aggre

49、gator that is hosted on their machine. Aggregator enquires about any new content uploaded on the server and then either makes note of the new content or downloads it to the clients browser.Web feeds are designed to be machine-readable rather than being human-readable, hence they can be used to autom

50、atically transfer information from one website to another without human intervention. The two main Web feed formats are RSS and Atom.RSS: RSS (Really Simple Syndication) is an XML based protocol, which when used with feeds and aggregators, offers website summaries and syndications. The RSS feeds tak

51、e the form of a single XML file that can be hosted and updated automatically by the website owners and accessed and read by RSS feed software. The RSS feed is an XML based document that has a global container RSS tag of format 2.0. This XML file has tags that define the main website, and provides se

52、t of item-tags representing links that have been published/updated on the site. Each such item-tag consists of a title, short description of the items and the links to the full text in XML format. The RSS feed reader software downloads this XML file and parses it to form HTML data that gets displaye

53、d on the users browser in the form of hyperlinks, pointing to the original website.Atom: There are two standards related to Atom-the Atom Syndication Formats is an XML language and the Atom Publishing Protocol is a simple HTTP-based protocol for creating and updating Web resource. The development of

54、 Atom was a result of incompatible version of RSS syndication and poor interoperability. Even though the functionality of RSS and Atom are some what similar, the intention with Atom is to make development of application easier with Web syndication feeds.RSS may either contain plain text or escaped H

55、TML as a payload, and there is no way to indicate which of the two is provided. In contrast to this, Atom uses an explicitly labeled payload container. Hence, more variety of payload types, like plain text, escaped HTML, XHTML, XML, Base64-encoded binary, is available in Atom and at the same time re

56、ference to third party content, like documents, video and audio streams can also be made available. Another point of difference between Atom and RSS is that Atom includes XML schema, whereas RSS does not.Web feeds are useful for any enterprise, if they plan to integrate it in their portal solution.

57、It can be used for showing corporate data as well, such as the latest software build status, network uptime, upcoming corporate meetings or other dashboard-like features.Road to Enterprise 2.0Collaboration and resource sharing have been two such headways shown by Web 2.0 that have envisioned enterpr

58、ises to try benefiting from them. Blogging and Wiki are two collaboration techniques that enterprises can look forward to integrate into their portal solutions. Adding a blog to enterprises portal will add a human interactive touch to a vendor-customer or management-employee relationship. Similarly,

59、 a central information repository can be created with the help of Wiki.As we have talked of Web feeds and mash-ups, they can be efficiently used in an enterprise. Through Web feeds, employees can keep themselves abreast with latest information of data stored in corporate applications. On other hand

60、mash-ups provide rich user interfaces that address the need for increased worker productivity, by making it easier for the user to find and use the information that he needs for a particular task or role.Many SaaS (Software as a Service) model based applications are now being developed, to be used a