问题 问答题

采用基于Web2.0的Mashup技术架构Web应用系统,可以从不同的数据源抽取数据,聚合并转换数据,在不同的上下文使用,避免了复杂的集成过程,近年来受到了广泛的关注。Mashup核心活动包括数据输入、数据可视化、调度与监视、剪裁、转换与充实、动作,以及发布与推广等。可以通过使用搜索、语言翻译、工作流支持和其他改进技术来增强基础的Mashup。

请围绕“基于Mashup的Web应用系统设计与应用”论题,依次从以下3个方面进行论述。

(1)概要叙述你参与管理和实施的Web应用系统开发项目及你所承担的主要工作。

(2)简述常见的Mashup数据接口,详细论述你在所参与建设的Web应用系统项目中是如何应用Mashup技术,并分析应用这些技术之后对项目产生了哪些效果(或影响)。

(3)论述在你参与建设的Web应用系统项目实施过程中遇到的,与Mashup技术相关的问题及解决的办法,还有哪些需要进一步改进之处及如何进行改进。

答案

参考答案:

(A)简要介绍你参与规划和设计的Web应用系统开发项目,尤其着重介绍Web应用系统的应用环境、总体需求(特别是质量属性需求)、Web应用系统的逻辑与物理拓扑结构、采用的技术等内容,简要说明自己在该项目中的角色、所承担的主要任务及开展的主要工作。参与设计和实施的Web应用系统项目应有一定的规模,自己在该项目中担任的主要工作应有一定的分量。

(B)Mashup程序从架构上是由客户机的Web浏览器、Mashup网站和API/内容提供者等C个不同的部分组成,它们在逻辑上和物理上都是相互脱离的(可能由网络和组织边界分隔)。Mashup的主要工作流程是:当移动用户向Mashup网站发起一个请求时,通过GPS系统附带自身的位置信息;Mashup网站接收请求,并将请求分解为对多个服务网站的数据请求调用,并为发起调用进行准备;针对不同服务网站的调用接口,采用不同的调用方式;最终在Mashup站点将请求信息进行数据内容聚合,并将用户所处位置的整合信息返回。目前,经常使用的C科Mashup接口如下。

①聚合内容(Really Simple Syndication, RSS)式的Mashup接口:一种用于对网站内容进行描述和同步的格式,是目前使用最为广泛的Web资源发布方式,可以被称为资源共享模式的延伸。

②表述性状态转移(REpresentational State Transfer, REST)式的Mashup接口:REST从资源的角度来看待整个网络,分布在各处的资源由统一资源标识符(Unified Resource Identifier, URI)确定,而客户端的应用通过URI来获取资源的表示。

③基于简单对象访问协议(Simple Object Access Protocol, SOAP)的Web服务式Mashup接口。一种基于XML的数据格式定义,用来进行Web服务调用过程中的参数调用和返回。

采用基于Web B.0的Mashup技术架构Web应用系统具有的优势:①仅需要使用现有Web应用程序(如Google Maps)公开的、基于Web的API(或Web服务)构建应用程序,集成过程相对简单;②直接使用Mashup技术集成两个或者更多的Web API,创建新的特性与功能;③使用Ajax技术调用基于Web的API,浏览器客户端不需要在每次与服务器通信时都重新加载整个页面,动态特性强;④使用SOA的思想集成底层系统,强调功能暴露与服务组合,以服务的形式集成并暴露现有系统的能力等。

在实现Mashup应用时,进行内容聚合的物理位置是一个十分重要的因素。目前很多Mashup站点都选择在客户端机器上进行内容聚合,构成所谓的胖因特网应用程序(Rich Internet Application, RIA)。这种在客户端进行内容聚合的优点主要表现在:①从Mashup服务器存储的角度来说,对服务器所产生的负载较轻,因为数据可以直接从内容提供者那里传送到客户端;②从网络传输的角度来说,在基于Ajax等技术和应用模型的基础上,客户端页面只请求需要更新的内容,而不用刷新整个页面,从而减少网络数据的通信量。

结合项目实践经验,说明你参与管理和开发的项目中,如何理解Mashup、门户、SOA、EAI/EII和SaaS之间的关系;能够全面和准确地描述Mashup各个核心活动(包括数据输入、数据可视化、调度与监视、剪裁、转换与充实、动作,以及发布与推广等)及其具体的实施内容;能够准确地描述如何管理Mashup开发,包括从计划和管理方法到集成、测试和部署的全过程:在优化安全性、隐私、可访问性、有用性和性能,通过使用搜索、语言翻译、工作流支持和其他改进来增强基础的Mashup,执行有效的负载和回归测试,避免造成企业Mashup故障的“反模式”等方面也要有一定的论述。

(C)有具体着眼点地论述在你参与建设的Web应用系统项目实施过程中遇到的,与Mashup技术相关的问题。针对具体的问题你采取了哪些解决技术、方法和措施,以及它们对该工程项目后期的工作产生了哪些积极(或消极)的影响(效果和存在的问题)。论文最后可以进一步讨论你在该工程项目中获得的与Mashup应用相关的体会,以及在今后的工作过程中,如果碰到类似的开发项目你将如何应用这些经验或教训。对需要进一步改进的地方,应有具体的着眼点,不能泛泛而谈。

单项选择题
单项选择题

I came across an old country guide the other day. It listed all the tradesmen in each village in my part of the country, and it was impressive to see the great variety of services which were available on one’s own doorstep in the late Victorian countryside.

Nowadays a superficial traveler in rural England might conclude that the only village tradesmen still flourishing were either selling frozen food to the inhabitants or selling antiques to visitors. Nevertheless, this would really be a false impression. Admittedly there has been a contraction of village commerce, but its vigor is still remarkable.

Our local grocer’s shop, for example, is actually expanding in spite of the competition from supermarkets in the nearest town. Women sensibly prefer to go there and exchange the local news while doing their shopping, instead of queueing up anonymously at a supermarket. And the proprietor knows well that personal service has a substantial cash value.

His prices may be a bit higher than those in the town, but he will deliver anything at any time. His assistants think nothing of bicycling down the village street in their lunch, hour to take a piece of cheese to an old-age pensioner who sent her order by word of mouth with a friend who happened to be passing. The more affluent customers telephone their shopping lists and the goods are on their doorsteps within an hour. They have only to hint at a fancy for some commodity outside the usual stock and the grocer a red-faced figure, instantly obtains it for them.

The village gains from this sort of enterprise, of course. But I also find it satisfactory because a village shop offers one of the few ways in which a modest individualist can still get along in the world without attaching himself to the big battalions of industry or commerce.

Most of the village shopkeepers I know, at any rate, are decidedly individualist in their ways. For exampie, our shoemaker is a formidable figure: a thick-set, irritable man whom children treat with marked respect, knowing that an ill-judged word can provoke an angry eruption at any time. He stares with contempt at the pairs of cheap, mass-produced shoes taken to him for repair: has it come to this, he seems to be saying, that he, a craftsman, should have to waste his skills upon such trash But we all know he will in fact do excellent work upon them. And he makes beautiful shoes for those who can afford such luxury.

The local grocer’s shop is expanding even though()

A. town shops are better at promotion

B. town shops are larger and more convenient

C.town shops enjoy price advantages

D. people get extra service in town shops