专利文献的英汉翻译-JSP的技术发展-中英文文献翻译

发布时间：2018-01-11 所属栏目：计算机软件及应用

一 : JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

THE TECHNIQUE DEVELOPMENT HISTORY OF JSP

By:Kathy Sierra and Bert Bates

Source: Servlet&JSP

The Java Server Pages( JSP) is a kind of according to web of the script plait distance technique, similar carries the script language of Java in the server of the Netscape company of server- side JavaScript( SSJS) and the Active Server Pages(ASP) of the Microsoft. JSP compares the SSJS and ASP to have better can expand sex, and it is no more exclusive than any factory or some one particular server of Web. Though the norm of JSP is to be draw up by the Sun company of, any factory can carry out the JSP on own system.

The After Sun release the JSP( the Java Server Pages) formally, the this kind of new Web application development technique very quickly caused the people's concern. JSP provided a special development environment for the Web application that establishes the high dynamic state. According to the Sun parlance, the JSP can adapt to include the Apache WebServer, IIS4.0 on the market at inside of 85% server product.

This chapter will introduce the related knowledge of JSP and Databases, and JavaBean related contents, is all certainly rougher introduction among them basic contents, say perhaps to is a Guide only, if the reader needs the more detailed information, pleasing the book of consult the homologous JSP.

1.1 GENERALIZE

The JSP(Java Server Pages) is from the company of Sun Microsystems initiate, the many companies the participate to the build up the together of the a kind the of dynamic the state web the page technique standard, the it have the it in the construction the of the dynamic state the web page the strong but the do not the especially of the function. JSP and the technique of ASP of the Microsoft is very alike. Both all provide the ability that mixes with a certain procedure code and is explain by the language engine to carry out the procedure code in the code of HTML. Underneath we are simple of carry on the introduction to it.

JSP pages are translated into servlets. So, fundamentally, any task JSP pages can perform could also be accomplished by servlets. However, this underlying equivalence does not mean that servlets and JSP pages are equally appropriate in all scenarios. The issue is not the power of the technology, it is the convenience, productivity, and maintainability of one or the other. After all, anything you can do on a particular computer platform in the Java programming language you could also do in assembly language. But it still matters which you choose. 1

河南理工大学毕业设计（论文）外文翻译

JSP provides the following benefits over servlets alone:

? It is easier to write and maintain the HTML. Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.

? You can use standard Web-site development tools. Even HTML tools that know nothing about JSP can be used because they simply ignore the JSP tags.

? You can divide up your development team. The Java programmers can work on the dynamic code. The Web developers can concentrate on the presentation layer. On large projects, this division is very important. Depending on the size of your team and the complexity of your project, you can enforce a weaker or stronger separation between the static HTML and the dynamic content.

Now, this discussion is not to say that you should stop using servlets and use only JSP instead. By no means. Almost all projects will use both. For some requests in your project, you will use servlets. For others, you will use JSP. For still others, you will combine them with the MVC architecture . You want the appropriate tool for the job, and servlets, by themselves, do not complete your toolkit.

1.2 SOURCE OF JSP

The technique of JSP of the company of Sun, making the page of Web develop the personnel can use the HTML perhaps marking of XML to design to turn the end page with format. Use the perhaps small script future life of marking of JSP becomes the dynamic state on the page contents.( the contents changes according to the claim of)

The Java Servlet is a technical foundation of JSP, and the large Web applies the development of the procedure to need the Java Servlet to match with with the JSP and then can complete, this name of Servlet comes from the Applet, the local translation method of now is a lot of, this book in order not to misconstruction, decide the direct adoption Servlet but don't do any translation, if reader would like to, can call it as" small service procedure". The Servlet is similar to traditional CGI, ISAPI, NSAPI etc. Web procedure development the function of the tool in fact, at use the Java Servlet hereafter, the customer need not use again the lowly method of CGI of efficiency, also need not use only the ability come to born page of Web of dynamic state in the method of API that a certain fixed Web server terrace circulate. Many servers of Web all support the Servlet, even not support the Servlet server of Web directly and can also pass the additional applied server and the mold pieces to support the Servlet. Receive benefit in the characteristic of the Java cross-platform, the Servlet is also a terrace irrelevant, actually, as long as match the norm of Java Servlet, the Servlet is complete to have nothing to do with terrace and is to have nothing to do with server of Web. Because the Java Servlet is internal to provide the service by the line distance, need not start a progress 2

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to the each claimses, and make use of the multi-threading mechanism can at the same time for several claim service, therefore the efficiency of Java Servlet is very high.

But the Java Servlet also is not to has no weakness, similar to traditional CGI, ISAPI, the NSAPI method, the Java Servlet is to make use of to output the HTML language sentence to carry out the dynamic state web page of, if develop the whole website with the Java Servlet, the integration process of the dynamic state part and the static state page is an evil-foreboding dream simply. For solving this kind of weakness of the Java Servlet, the SUN released the JSP.

A number of years ago, Marty was invited to attend a small 20-person industry roundtable discussion on software technology. Sitting in the seat next to Marty was James Gosling, inventor of the Java programming language. Sitting several seats away was a high-level manager from a very large software company in Redmond, Washington. During the discussion, the moderator brought up the subject of Jini, which at that time was a new Java technology. The moderator asked the manager what he thought of it, and the manager responded that it was too early to tell, but that it seemed to be an excellent idea. He went on to say that they would keep an eye on it, and if it seemed to be catching on, they would follow his company's usual "embrace and extend" strategy. At this point, Gosling lightheartedly interjected "You mean disgrace and distend."

Now, the grievance that Gosling was airing was that he felt that this company would take technology from other companies and suborn it for their own purposes. But guess what? The shoe is on the other foot here. The Java community did not invent the idea of designing pages as a mixture of static HTML and dynamic code marked with special tags. For example, Cold Fusion did it years earlier. Even ASP (a product from the very software company of the aforementioned manager) popularized this approach before JSP came along and decided to jump on the bandwagon. In fact, JSP not only adopted the general idea, it even used many of the same special tags as ASP did.

The JSP is an establishment at the model of Java servlets on of the expression layer technique, it makes the plait write the HTML to become more simple.Be like the SSJS, it also allows you carry the static state HTML contents and servers the script mix to put together the born dynamic state exportation. JSP the script language that the Java is the tacit approval, however, be like the ASP and can use other languages( such as JavaScript and VBScript), the norm of JSP also allows to use other languages.

1.3JSP CHARACTERISTICS

Is a service according to the script language in some one language of the statures system this kind of discuss, the JSP should be see make is a kind of script language. 3

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However, be a kind of script language, the JSP seemed to be too strong again, almost can use all Javas in the JSP.

Be a kind of according to text originally of, take manifestation as the central development technique, the JSP provided all advantages of the Java Servlet, and, when combine with a JavaBeans together, providing a kind of make contents and manifestation that simple way that logic separate. Separate the contents and advantage of logical manifestations is, the personnel who renews the page external appearance need not know the code of Java, and renew the JavaBeans personnel also need not be design the web page of expert in hand, can use to take the page of JavaBeans JSP to define the template of Web, to build up a from have the alike external appearance of the website that page constitute. JavaBeans completes the data to provide, having no code of Java in the template thus, this means that these templates can be written the personnel by a HTML plait to support. Certainly, can also make use of the Java Servlet to control the logic of the website, adjust through the Java Servlet to use the way of the document of JSP to separate website of logic and contents.

Generally speaking, in actual engine of JSP, the page of JSP is the edit and translate type while carry out, not explain the type of. Explain the dynamic state web page development tool of the type, such as ASP, PHP3 etc., because speed etc. reason, have already can't satisfy current the large electronic commerce needs appliedly, traditional development techniques are all at to edit and translate the executive way change, such as the ASP → ASP+;PHP3 → PHP4.

In the JSP norm book, did not request the procedure in the JSP code part( be called the Scriptlet) and must write with the Java definitely. Actually, have some engines of JSP are adoptive other script languages such as the EMAC- Script, etc., but actually this a few script languages also are to set up on the Java, edit and translate for the Servlet to carry out of. Write according to the norm of JSP, have no Scriptlet of relation with Java also is can of, however, mainly lie in the ability and JavaBeans, the Enterprise JavaBeanses because of the JSP strong function to work together, so even is the Scriptlet part not to use the Java, edit and translate of performance code also should is related with Java.

1.4JSP MECHANISM

To comprehend the JSP how unite the technical advantage that above various speak of, come to carry out various result easily, the customer must understand the differentiation of" the module develops for the web page of the center" and" the page develops for the web page of the center" first.

The SSJS and ASP are all in several year ago to release, the network of that time is still very young, no one knows to still have in addition to making all business, datas and the 4

河南理工大学毕业设计（论文）外文翻译

expression logic enter the original web page entirely heap what better solve the method. This kind of model that take page as the center studies and gets the very fast development easily. However, along with change of time, the people know that this kind of method is unwell in set up large, the Web that can upgrade applies the procedure. The expression logic write in the script environment was lock in the page, only passing to shear to slice and glue to stick then can drive heavy use. Express the logic to usually mix together with business and the data logics, when this makes be the procedure member to try to change an external appearance that applies the procedure but do not want to break with its llied business logic, apply the procedure of maintenance be like to walk the similar difficulty on the eggshell. In fact in the business enterprise, heavy use the application of the module already through very mature, no one would like to rewrite those logics for their applied procedure.HTML and sketch the designer handed over to the implement work of their design the Web plait the one who write, make they have to double work- Usually is the handicraft plait to write, because have no fit tool and can carry the script and the HTML contents knot to the server to put together. Chien but speech, apply the complexity of the procedure along with the Web to promote continuously, the development method that take page as the center limits sex to become to get up obviously.

At the same time, the people always at look for the better method of build up the Web application procedure, the module spreads in customer's machine/ server the realm. JavaBeans and ActiveX were published the company to expand to apply the procedure developer for Java and Windows to use to come to develop the complicated procedure quickly by" the fast application procedure development"( RAD) tool. These techniques make the expert in the some realm be able to write the module for the perpendicular application plait in the skill area, but the developer can go fetch the usage directly but need not control the expertise of this realm.

Be a kind of take module as the central development terrace, the JSP appeared. It with the JavaBeans and Enterprise JavaBeans( EJB) module includes the model of the business and the data logic for foundation, provide a great deal of label and a script terraces to use to come to show in the HTML page from the contents of JavaBeans creation or send a present in return. Because of the property that regards the module as the center of the JSP, it can drive Java and not the developer of Java uses equally. Not the developer of Java can pass the JSP label( Tags) to use the JavaBeans that the deluxe developer of Java establish. The developer of Java not only can establish and use the JavaBeans, but also can use the language of Java to come to control more accurately in the JSP page according to the expression logic of the first floor JavaBeans.

河南理工大学毕业设计（论文）外文翻译

See now how JSP is handle claim of HTTP. In basic claim model, a claim directly was send to JSP page in. The code of JSP controls to carry on hour of the logic processing and module of JavaBeanses' hand over with each other, and the manifestation result in dynamic state bornly, mixing with the HTML page of the static state HTML code. The Beans can be JavaBeans or module of EJBs. Moreover, the more complicated claim model can see make from is request other JSP pages of the page call sign or Java Servlets.

The engine of JSP wants to chase the code of Java that the label of JSP, code of Java in the JSP page even all converts into the big piece together with the static state HTML contents actually. These codes piece was organized the Java Servlet that customer can not see to go to by the engine of JSP, then the Servlet edits and translate them automatically byte code of Java.

Thus, the visitant that is the website requests a JSP page, under the condition of it is not knowing, an already born, the Servlet actual full general that prepared to edit and translate completes all works, very concealment but again and efficiently. The Servlet is to edit and translate of, so the code of JSP in the web page does not need when the every time requests that page is explain. The engine of JSP need to be edit and translate after Servlet the code end is modify only once, then this Servlet that editted and translate can be carry out. The in view of the fact JSP engine auto is born to edit and translate the Servlet also, need not procedure member begins to edit and translate the code, so the JSP can bring vivid sex that function and fast developments need that you are efficiently.

Compared with the traditional CGI, the JSP has the equal advantage. First, on the speed, the traditional procedure of CGI needs to use the standard importation of the system to output the equipments to carry out the dynamic state web page born, but the JSP is direct is mutually the connection with server. And say for the CGI, each interview needs to add to add a progress to handle, the progress build up and destroy by burning constantly and will be a not small burden for calculator of be the server of Web. The next in order, the JSP is specialized to develop but design for the Web of, its purpose is for building up according to the Web applied procedure, included the norm and the tool of a the whole set. Use the technique of JSP can combine a lot of JSP pages to become a Web application procedure very expediently.

河南理工大学毕业设计（论文）外文翻译

JSP的技术发展历史

作者： Kathy Sierra and Bert Bates

来源： Servlet&JSP

Java Server Pages(JSP)是一种基于web的脚本编程技术，类似于网景公司的服务器端Java脚本语言—— server-side JavaScript(SSJS)和微软的Active Server Pages(ASP)。与SSJS和ASP相比，JSP具有更好的可扩展性，并且它不专属于任何一家厂商或某一特定的Web服务器。尽管JSP规范是由Sun公司制定的，但任何厂商都可以在自己的系统上实现JSP。

在Sun正式发布JSP(Java Server Pages)之后，这种新的Web应用开发技术很快引起了人们的关注。JSP为创建高度动态的Web应用提供了一个独特的开发环境。按照Sun的说法，JSP能够适应市场上包括Apache WebServer、IIS4.0在内的85%的服务器产品。本文将介绍JSP相关的知识，以及JavaBean的相关内容，当然都是比较粗略的介绍其中的基本内容，仅仅起到抛砖引玉的作用，如果读者需要更详细的信息，请参考相应的JSP的书籍。

1.1 概述

JSP(Java Server Pages)是由Sun Microsystems公司倡导、许多公司参与一起建立的一种动态网页技术标准，其在动态网页的建设中有其强大而特别的功能。JSP与Microsoft的ASP技术非常相似。两者都提供在HTML代码中混合某种程序代码、由语言引擎解释执行程序代码的能力。下面我们简单的对它进行介绍。

JSP页面最终会转换成servlet。因而，从根本上，JSP页面能够执行的任何任务都可以用servlet来完成。然而，这种底层的等同性并不意味着servlet和JSP页面对于所有的情况都等同适用。问题不在于技术的能力，而是二者在便利性、生产率和可维护性上的不同。毕竟，在特定平台上能够用Java编程语言完成的事情，同样可以用汇编语言来完成，但是选择哪种语言依旧十分重要。

和单独使用servlet相比，JSP提供下述好处：

JSP中HTML的编写与维护更为简单。JSP中可以使用常规的HTML：没有额外的反斜杠，没有额外的双引号，也没有暗含的Java语法。

能够使用标准的网站开发工具。即使是那些对JSP一无所知的HTML工具，我们也可以使用，因为它们会忽略JSP标签（JSP tags）。

可以对开发团队进行划分。Java程序员可以致力于动态代码。Web开发人员可以将 7

河南理工大学毕业设计（论文）外文翻译

经理集中在表示层（presentation layer）上。对于大型的项目，这种划分极为重要。依据开发团队的大小，及项目的复杂程度，可以对静态HTML和动态内容进行弱分离（weaker separation）和强分离（stronger separation）。

此处的讨论并不是说人们应该放弃使用servlet而仅仅使用JSP。事实上，几乎所有的项目都会同时用到这两种技术。在某些项目中，更适宜选用servlet，而针对项目中的某些请求，我们可能会在MVC构架下组合使用这两项技术。我们总是希望用适当的工具完成相对应的工作，仅仅是servlet并不一定能够胜任所有工作。

1.2 JSP的由来

Sun公司的JSP技术，使Web页面开发人员可以使用HTML或者XML标识来设计和格式化最终页面。使用JSP标识或者小脚本来生成页面上的动态内容(内容是根据请求来变化的)。

Java Servlet是JSP技术的基础，而且大型的Web应用程序的开发需要Java Servlet和JSP配合才能完成，Servlet这个名称源于Applet，现在国内的翻译方式很多，本书为了避免误会，决定直接采用Servlet而不做任何翻译，读者如果愿意，可以称之为“小服务程序”。Servlet其实和传统的CGI、ISAPI、NSAPI等Web程序开发工具的作用是相似的，在使用Java Servlet以后，用户不必再使用效率低下的CGI方式，也不必使用只能在某个固定Web服务器平台运行的API方式来动态生成Web页面。许多Web服务器都支持Servlet，即使不直接支持Servlet的Web服务器也可以通过附加的应用服务器和模块来支持Servlet。得益于Java的跨平台的特性，Servlet也是平台无关的，实际上，只要符合Java Servlet规范，Servlet是完全与平台无关且是与Web服务器无关的。由于Java Servlet内部是以线程方式提供服务，不必对于每个请求都启动一个进程，并且利用多线程机制可以同时为多个请求服务，因此Java Servlet效率非常高。

但Java Servlet也不是没有缺点，和传统的CGI、ISAPI、NSAPI方式相同，Java Servlet是利用输出HTML语句来实现动态网页的，如果用Java Servlet来开发整个网站，动态部分和静态页面的整合过程会非常难以实现。为了解决Java Servlet的这种缺点，SUN推出了JSP。

许多年前，Marty受到邀请,参加一个有关软件技术的小型研讨会.坐在Marty旁边的人是James Gosling--- Java编程语言的发明者。隔几个位置,是来自华盛顿一家大型软件公司的高级经理。在讨论过程中,研讨会的主席提出了Jini的议题,这在当时是一项新的Java技术。主席向该经理询问他的想法.他回答说,虽然现在言之过早，但这看起来会是非常有前途的一项技术。他们会持续关注这项技术,如果这项技术变得流行起来,他们会遵循公司的“接受并扩充(embrace and extend)”的策略.此时, Gosling随意地插话说“你的意思其实就是不接受且不扩充(disgrace and distend)。”

在此, Gosling的抱怨显示出，他感到这个公司会从其他公司那里拿走技术,用于他们自己的目的.出人意料的是，形势已经完全不同。Java团队并没有发明这一思想---- 8

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将页面设计成由静态HTML和用特殊标签标记的动态代码混合组成.。ColdFusion多年前就已经这样做了。甚至ASP(来自于前述经理所在公司的一项产品)都在JSP出现之前推广了这种方式。实际上,JSP不只采用了这种通用概念,它甚至使用许多和ASP相同的特殊标签。

JSP是建立在Java servlets模型之上的表达层技术，它使编写HTML变得更简单。像SSJS一样，它也允许你将静态HTML内容与服务器端脚本混合起来生成动态输出。JSP把Java作为默认的脚本语言，然而，就像ASP可以使用其他语言(如JavaScript和VBScript)一样，JSP规范也允许使用其他语言。

1.3 JSP的特点

按照脚本语言是服务于某一个子系统的语言这种论述，JSP应当被看作是一种脚本语言。然而，作为一种脚本语言，JSP又显得过于强大了，在JSP中几乎可以使用全部的Java类。

作为一种基于文本的、以显示为中心的开发技术，JSP提供了Java Servlet的所有好处，并且，当与一个JavaBeans类结合在一起时，JSP提供了一种使内容和显示逻辑分开的简单方式。分开内容和显示逻辑的好处是，更新页面外观的人员不必懂得Java代码，而更新JavaBeans类的人员也不必是设计网页的行家里手，就可以用带JavaBeans类的JSP页面来定义Web模板，以建立一个由具有相似的外观的页面组成的网站。JavaBeans类完成数据提供，这样在模板中就没有Java代码，这意味着这些模板可以由一个HTML编写人员来维护。当然，也可以利用Java Servlet来控制网站的逻辑，通过Java Servlet调用JSP文件的方式来将网站的逻辑和内容分离。

一般来说，在实际的JSP引擎中，JSP页面在执行时是编译式，而不是解释式的。解释式的动态网页开发工具如ASP、PHP3等由于速度等原因已经满足不了当前大型电子商务应用的需要了，传统的开发技术都在向编译执行的方式改变，如ASP→ASP+；PHP3→PHP4。

在JSP规范书中，并没有明确要求JSP中的程序代码部分(称为Scriptlet)一定要用Java来写。实际上，有一些JSP引擎就是采用的其他脚本语言，如EMAC-Script、WebL等，但实际上这几种脚本语言也是构建在Java上面，编译为Servlet来实现的。按照JSP规范书写，和Java没有任何关系的Scriptlet也是可以的，不过，由于JSP的强大功能主要在于能和JavaBeans、Enterprise JavaBeans共同运转，所以即使是Scriptlet部分不使用Java，编译成的执行代码也应该是与Java相关的。

1.4 JSP的机制

要理解JSP怎样联合以上各种所提到的技术的优点，从而轻而易举地实现各种效果，用户必须首先了解“组件为中心的网页开发”和“页面为中心的网页开发”的区别。

SSJS和ASP都是在几年前推出的，那时网络还很年轻，没有人知道除了把所有的商务、数据和表达逻辑统统堆进原始网页中之外还有什么更好的解决方法。这种以页面 9

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为中心的模型容易学习并且得到相当快速的发展。然而，随着时间的推移，人们认识到这种方法不适于构建大型的、可升级的Web应用程序。在脚本环境中书写的表达逻辑被锁在页面内，只有通过剪切和粘贴才能被重用。表达逻辑通常和商务及数据逻辑混在一起，这使得当程序员试图改变一个应用程序的外观而不想破坏与之紧密结合的商务逻辑时，应用程序的维护就变得十分艰难。其事实上，企业中可重用组件的应用早已经很成熟，没有人愿意为它们的应用程序重写那些逻辑。HTML和图形设计师把它们的设计的实施工作交给了Web编写者，使他们不得不加倍工作—— 常常是手工编写，因为没有合适的工具可以把服务器端脚本与HTML内容结合起来。简而言之，随着Web应用程序的复杂性不断提升，以页面为中心的开发方式的局限性变得明显起来。

与此同时，人们一直在寻找建立Web应用程序的更好方法，组件在客户机/服务器领域流行起来。JavaBeans和ActiveX被“快速应用程序开发”(RAD)工具发行商推广给Java和Windows应用程序开发者用来快速开发复杂的程序。这些技术使某领域内的专家可以为本领域内的垂直应用编写组件，而开发者可以直接拿来使用而不必掌握这一领域的专门技术。

作为一种以组件为中心的开发平台，JSP出现了。它以JavaBeans和Enterprise JavaBeans(EJB)组件包含商务和数据逻辑的模型为基础，提供大量标签和一个脚本平台用来在HTML页中显示由JavaBeans产生或回送的内容。由于JSP的以组件为中心的性质，它可以被Java和非Java开发者同样使用。非Java开发者可以通过JSP的标签(Tags)来使用高级Java开发者创建的JavaBeans。Java开发者不仅可以创建和使用JavaBeans，还能在JSP页中使用Java语言来更精密地控制基于底层JavaBeans的表达逻辑。

现在来看看JSP是如何处理HTTP请求的。在基本请求模型中，一个请求直接被送到JSP页中。JSP代码控制着进行逻辑处理时与JavaBeans组件的交互，并在动态生成的、混合了静态HTML代码的HTML页中显示结果。Beans 可以是JavaBeans 或EJB组件。另外，更加复杂的请求模型可看作从被请求页呼叫其他JSP页或Java Servlets。

JSP引擎实际上要把JSP标签、JSP页中的Java代码甚至连同静态HTML内容都转换为大块的Java代码。这些代码块被JSP引擎组织到用户看不到的Java Servlet中去，然后Servlet自动把它们编译成Java字节码。这样，当网站的访问者请求一个JSP页时，在它不知道的情况下，一个已经生成的、预编译过的Servlet实际上将完成所有的工作，非常隐蔽而又高效。因为Servlet是编译过的，所以网页中的JSP代码不需要在每次请求该页时被解释一遍。JSP引擎只需在Servlet代码最后被修改后编译一次，然后这个编译过的Servlet就可以被执行了。由于是JSP引擎自动生成并编译Servlet，不用程序员动手编译代码，所以JSP能带给你高效的性能和快速开发所需的灵活性。

和传统的CGI相比较，JSP有相当的优势。首先，在速度上，传统的CGI程序需要使用系统的标准输入输出设备来实现动态网页的生成，而JSP是直接和服务器相关联的。而且对于CGI来说，每一个访问就需要新增加一个进程来处理，进程不断地建立和销毁 10

河南理工大学毕业设计（论文）外文翻译

对于作为Web服务器的计算机将是不小的负担。其次，JSP是专门为Web开发而设计的，其目的是为了建立基于Web的应用程序，其中包含了一整套的规范和工具。使用JSP技术可以很方便地将一大堆JSP页面组合成为一个Web应用程序。

二 : PLC相关的外文英语文献与翻译

Relays

The Programmable Logic Controller

Early machines were controlled by mechanical means using cams, gears, levers and other basic mechanical devices. As the complexity grew, so did the need for a more sophisticated control system. This system contained wired relay and switch control elements. These elements were wired as required to provide the control logic necessary for the particular type of machine operation. This was acceptable for a machine that never needed to be changed or modified, but as manufacturing techniques improved and plant changeover to new products became more desirable and necessary, a more versatile means of controlling this equipment had to be developed. Hardwired relay and switch logic was cumbersome and time consuming to modify. Wiring had to be removed and replaced to provide for the new control scheme required. This modification was difficult and time consuming to design and install and any small "bug" in the design could be a major problem to correct since that also required rewiring of the system. A new means to modify control circuitry was needed. The development and testing ground for this new means was the U.S. auto industry. The time period was the late 1960's and early 1970's and the result was the programmable logic controller, or PLC. Automotive plants were confronted with a change in manufacturing techniques every time a model changed and, in some cases, for changes on the same model if improvements had to be made during the model year. The PLC provided an easy way to reprogram the wiring rather than actually rewiring the control system.

The PLC that was developed during this time was not very easy to program. The language was cumbersome to write and required highly trained programmers. These early devices were merely relay replacements and could do very little else. The PLC has at first gradually, and in recent years rapidly developed into a sophisticated and highly versatile control system component. Units today are capable of performing complex math functions including numerical integration and differentiation and operate at the fast microprocessor speeds now available. Older PLCs were capable of only handling discrete inputs and outputs (that is, on-off type signals), while today's systems can accept and generate analog voltages

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and currents as well as a wide range of voltage levels and pulsed signals. PLCs are also designed to be rugged. Unlike their personal computer cousin, they can typically withstand vibration, shock, elevated temperatures, and electrical noise to which manufacturing equipment is exposed.

As more manufacturers become involved in PLC production and development, and PLC capabilities expand, the programming language is also expanding. This is necessary to allow the programming of these advanced capabilities. Also, manufacturers tend to develop their own versions of ladder logic language (the language used to program PLCs). This complicates learning to program PLC's in general since one language cannot be learned that is applicable to all types. However, as with other computer languages, once the basics of PLC operation and programming in ladder logic are learned, adapting to the various manufacturers’ devices is not a complicated process. Most system designers eventually settle on one particular manufacturer that produces a PLC that is personally comfortable to program and has the capabilities suited to his or her area of applications.

It should be noted that in usage, a programmable logic controller is generally referred to as a “PLC” or “programmable controller”. Although the term “programmable controller” is generally accepted, it is not abbreviated “PC” because the abbreviation “PC” is usually used in reference to a personal computer. As we will see in this chapter, a PLC is by no means a personal computer.

Programmable controllers (the shortened name used for programmable logic controllers) are much like personal computers in that the user can be overwhelmed by the vast array of options and configurations available. Also, like personal computers, the best teacher of which one to select is experience. As one gains experience with the various options and configurations available, it becomes less confusing to be able to select the unit that will best perform in a particular application.

The typical system components for a modularized PLC are:

1. Processor.

The processor (sometimes call a CPU), as in the self contained units, is generally specified according to memory required for the program to beimplemented. In the

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modularized versions, capability can also be a factor. This includes features such as higher math functions, PID control loops and optional programming commands. The processor consists of the microprocessor, system memory, serial communication ports for printer, PLC LAN link and external programming device and, in some cases, the system power supply to power the processor and I/O modules.

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2. Mounting rack.

This is usually a metal framework with a printed circuit board backplane which provides means for mounting the PLC input/output (I/O) modules and processor. Mounting racks are specified according to the number of modules required to implement the system. The mounting rack provides data and power connections to the processor and modules via the backplane. For CPUs that do not contain a power supply, the rack also holds the modular power supply. There are systems in which the processor is mounted separately and connected by cable to the rack. The mounting rack can be available to mount directly to a panel or can be installed in a standard 19" wide equipment cabinet. Mounting racks are cascadable so several may be interconnected to allow a system to accommodate a large number of I/O modules.

3. Input and output modules.

Input and output (I/O) modules are specified according to the input and output signals associated with the particular application. These modules fall into the categories of discrete, analog, high speed counter or register types.

Discrete I/O modules are generally capable of handling 8 or 16 and, in some cases 32, on-off type inputs or outputs per module. Modules are specified as input or output but generally not both although some manufacturers now offer modules that can be configured with both input and output points in the same unit. The module can be specified as AC only, DC only or AC/DC along with the voltage values for which it is designed.

Analog input and output modules are available and are specified according to the desired resolution and voltage or current range. As with discrete modules, these are generally input or output; however some manufacturers provide analog input and output in the same module. Analog modules are also available which can directly accept thermocouple inputs

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for temperature measurement and monitoring by the PLC.

Pulsed inputs to the PLC can be accepted using a high speed countermodule. This module can be capable of measuring the frequency of an inputsignal from a tachometer or other frequency generating device. These modules can also count the incoming pulses if desired. Generally, both frequency and count are available from the same module at the same time if both are required in the application.

Register input and output modules transfer 8 or 16 bit words of information to and from the PLC. These words are generally numbers (BCD or Binary) which are generated from thumbwheel switches or encoder systems for input or data to be output to a display device by the PLC.

Other types of modules may be available depending upon the manufacturer of the PLC and it's capabilities. These include specialized communication modules to allow for the transfer of information from one controller to another. One new development is an I/O Module which allows the serial transfer of information to remote I/O units that can be as far as 12,000 feet away.

4. Power supply.

The power supply specified depends upon the manufacturer's PLC being utilized in the application. As stated above, in some cases a power supply capable of delivering all required power for the system is furnished as part of the processor module. If the power supply is a separate module, it must be capable of delivering a current greater than the sum of all the currents needed by the other modules. For systems with the power supply inside the CPU module, there may be some modules in the system which require excessive power not available from the processor either because of voltage or current requirements that can only be achieved through the addition of a second power source. This is generally true if analog or external communication modules are present since these require ± DC supplies which, in the case of analog modules, must be well regulated.

5. Programming unit.

The programming unit allows the engineer or technician to enter and edit the program to be executed. In it's simplest form it can be a hand held device with a keypad for program

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entry and a display device (LED or LCD) for viewing program steps or functions, as shown. More advanced systems employ a separate personal computer which allows the programmer to write, view, edit and download the program to the PLC. This is accomplished with proprietary software available from the PLC manufacturer. This software also allows the programmer or engineer to monitor the PLC as it is running the program. With this monitoring system, such things as internal coils, registers, timers and other items not visible externally can be monitored to determine proper operation. Also, internal register data can be altered if required to fine tune program operation. This can be advantageous when debugging the program. Communication with the programmable controller with this system is via a cable connected to a special programming port on the controller. Connection to the personal computer can be through a serial port or from a dedicated card installed in the computer.

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A Programmable Controller is a specialized computer. Since it is a computer, it has all the basic component parts that any other computer has; a Central Processing Unit, Memory, Input Interfacing and Output Interfacing.

The Central Processing Unit (CPU) is the control portion of the PLC. It interprets the program commands retrieved from memory and acts on those commands. In present day PLC's this unit is a microprocessor based system. The CPU is housed in the processor module of modularized systems.

Memory in the system is generally of two types; ROM and RAM. The ROM memory contains the program information that allows the CPU to interpret and act on the Ladder Logic program stored in the RAM memory. RAM memory is generally kept alive with an on-board battery so that ladder programming is not lost when the system power is removed. This battery can be a standard dry cell or rechargeable nickel-cadmium type. Newer PLC units are now available with Electrically Erasable Programmable Read Only Memory (EEPROM) which does not require a battery. Memory is also housed in the processor module in modular systems.

Input units can be any of several different types depending on input signals expected as described above. The input section can accept discrete or analog signals of various voltage and current levels. Present day controllers offer discrete signal inputs of both AC and DC

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voltages from TTL to 250 VDC and from 5 to 250 VAC. Analog input units can accept input levels such as ±10 VDC, ±5 VDC and 4-20 ma. current loop values. Discrete input units present each input to the CPU as a single 1 or 0 while analog input units contain analog to digital conversion circuitry and present the input voltage to the CPU as binary number normalized to the maximum count available from the unit. The number of bits representing the input voltage or current depends upon the resolution of the unit. This number generally contains a defined number of magnitude bits and a sign bit. Register input units present the word input to the CPU as it is received (Binary or BCD).

Output units operate much the same as the input units with the exception that the unit is either sinking (supplying a ground) or sourcing (providing a voltage) discrete voltages or sourcing analog voltage or current. These output signals are presented as directed by the CPU. The output circuit of discrete units can be transistors for TTL and higher DC voltage or Triacs for AC voltage outputs. For higher current applications and situations where a physical contact closure is required, mechanical relay contacts are available. These higher currents, however, are generally limited to about 2-3 amperes. The analog output units have internal circuitry which performs the digital to analog conversion and generates the variable voltage or current output.

The first thing the PLC does when it begins to function is update I/O. This means that all discrete input states are recorded from the input unit and all discrete states to be output are transferred to the output unit. Register data generally has specific addresses associated with it for both input and output data referred to as input and output registers. These registers are available to the input and output modules requiring them and are updated with the discrete data. Since this is input/output updating, it is referred to as I/O Update. The updating of discrete input and output information is accomplished with the use of input and output image registers set aside in the PLC memory. Each discrete input point has associated with it one bit of an input image register. Likewise, each discrete output point has one bit of an output image register associated with it. When I/O updating occurs, each input point that is ON at that time will cause a 1 to be set at the bit address associated with that particular input. If the input is off, a 0 will be set into the bit address. Memory in today's PLC's is generally

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configured in 16 bit words. This means that one word of memory can store the states of 16 discrete input points. Therefore, there may be a number of words of memory set aside as the input and output image registers. At I/O update, the status of the input image register is set according to the state of all discrete inputs and the status of the output image register is transferred to the output unit. This transfer of information typically only occurs at I/O update. It may be forced to occur at other times in PLC's which have an Immediate I/O Update command. This command will force the PLC to update the I/O at other times although this would be a special case.

Before a study of PLC programming can begin, it is important to gain a fundamental understanding of the various types of PLCs available, the advantages and disadvantages of each, and the way in which a PLC executes a program. The open frame, shoebox, and modular PLCs are each best suited to specific types of applications based on the environmental conditions, number of inputs and outputs, ease of expansion, and method of entering and monitoring the program. Additionally, programming requires a prior knowledge of the manner in which a PLC receives input information, executes a program, and sends output information. With this information, we are now prepared to begin a study of PLC programming techniques.

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When writing programs for PLCs, it is beneficial to have a background in ladder diagramming for machine controls. This is basically the material that was covered in Chapter 1 of this text. The reason for this is that at a fundamental level, ladder logic programs for PLCs are very similar to electrical ladder diagrams. This is no coincidence.The engineers that developed the PLC programming language were sensitive to the fact that most engineers, technicians and electricians who work with electrical machines on a day-to-day basis will be familiar with this method of representing control logic. This would allow someone new to PLCs, but familiar with control diagrams, to be able to adapt very quickly to the programming language. It is likely that PLC programming language is one of the easiest programming languages to learn.

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可编程序控制器

早期的机器用机械的方法采用凸轮控制、齿轮、杠杆和其他基本机械设备。［www.61k.com]增长的复杂性,因此需要一种更了复杂的控制系统。该系统包含有线继电器和开关控制元素。这些元素,要求提供有线控制逻辑的必要特定类型的机器上运行。这是一台机器,不接受需要变更或修改,但作为制造技术改进和植物转换为新产品变得更加理想的和必要的,一个更加多才多艺该设备具有控制手段,发展。继电器和开关特性的逻辑是笨重,费时要修改。线路必须拆卸和更换提供新的控制方案的要求。这个修改是针对设计、安装、消费的设需要正确接线系统。一个新的方式修改控制电路是需要的。开发和测试基地为这个新的方法美国的汽车工业。晚的时间是1960年代至1970年代初,结果是采用可编程序控制器PLC。面对汽车需要改变生产工艺改变每一次模型,在某些情况下,改善同一模型是在做了模型的一年。PLC提供一个简单的方法来重组接线,而不是实际电路重组的控制系统。

开发了PLC,在这段时间里是不太容易计划的。这PLC语言是难于书写和需要受过高度训练的程序员。这些早期的仅仅是传递装置,可以随心所欲的做很少就可以完成预先的任务。PLC在近年来迅速发展成为一种具有非常高的通用性控制系统的组成部分。今天已经能够执行复杂的运算功能包括数值积分的分化与已开放操作快速处理器的速度。曾经的PLC可只处理离散输入输出(即开关式信号),而今天的系统能够接受并产生模拟的电压和电流以及广泛的电压水平和脉冲信号。PLC设计的目的也是非常明确的。不像个人电脑,它们可以典型地操作振动、冲击、高温、电子噪声、生产设备暴露等。

随着越来越多的厂商卷入了可编程序控制器(PLC)的生产和开发,以及可编程序控制器(PLC)能力的拓展,编程语言也就随之增强了。需要这些先进的编程能力是有必要的。同时,制造商往往发展自己版本的使用于语言程序(PLC)的梯形逻辑语言。这个复杂可编程逻辑控制器(PLC)在学习编程的时候,既然一个可适用于所有的类型语言不能完全做到了解。然而,就像其他的计算机语言一样,可编程序控制器(PLC)的基本操作和编程逻辑是有学习阶段，去适应不同厂家的设备，这不是一个复杂的过程。大多数的系统设计师最终在一个特定的制造厂商自己产生一个可编程序控制器(PLC)的程序并具备适合它的地区性的应用能力。

应该指出的是,使用一个可编程逻辑控制器,普遍被称为“PLC”或“可编程控制

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器”。(www.61k.com］虽然术语“可编程控制器”已被普遍接受,但它并不是缩写“PC”，因为简称的“PC”通常用于个人电脑。正如我们所看到的, PLC控制绝不是一台个人电脑。

可编程控制器(缩短名字用于可编程逻辑控制器)像个人电脑用户可以做出了巨量的选择和配置。来到使用者面前,就像个人电脑，是最好老师的一个很好的选择。考虑到不同的收益和配置的选择,它就可以选择单位，使其变得能够将最好地履行在一个特定的应用。

典型的系统部件模块化可编程序控制器(PLC)是:

1、处理器

处理器(有时叫一个CPU),就像在独立控制单元,通常是根据指定的内存需求为程序是什么实施。在模块化的版本,能力也可以是一个重要的因素。这包括高等数学功能等特点,采用PID控制回路可编程的命令。处理器构成的微处理器、系统内存,串行通讯港口打印机,可编程序控制器(PLC)局域网连接装置和外部编程,在某些情况下,该系统供电电源处理器和I / O模块。

2、安装架

这通常是金属框架,印刷电路板提供用于安装底板意味着PLC输入/输出(I / O)模块和处理器。指定安装架是根据模块的数量必须执行系统。安装架提供数据和电力连接处理器与模块通过底板。对于cpu,它不包含一个电源、架子上也成立这种模块化的电力供应。有系统处理器安装连接电缆单独架子上。安装架能可直接向山面板或者可以安装在标准19“宽设备内阁。cascadable安装架是这么多允许一个系统互连来容纳大量I / O模块。

3。输入和输出模块

输入和输出(I / O)模块根据输入指定输出信号与之关联的特定应用程序。这些模块秋天分成离散、模拟、高速计数器或注册类型。

离散I / O模块一般都是有能力处理8和16,在某些情况下,开关类型的输入和输出一个模块。模块指定为输入或输出,但一般虽然一些制造商们提供了模块可配置和输入输出点在同一单元内。

模拟输入和输出模块都是可行的,适用于在合同中规定的预期的分辨率和电压或电流范围。随着这些都是一般离散输入或输出模块,一些制造商就在相同的模块提供模拟的输入和输出。PLC模拟模块也可以输入可直接接受热电偶的温度测量和监测。

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脉冲输入与可编程序控制器(PLC)可以接受使用高速计数器模块。（www.61k.com）这一个模块能够从一个转速或其他频率产生装置测量频率的一个输入信号。这些模块也可以计算想要的脉冲计数。一般来说, 如果双方都需要应用程序，在同一时间内，两个频率和计数可从相同的模块执行。

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输入和输出模块寄存器从PLC传递8和16位字信息。这些就是一般编号(BCD码或二进制), 由PLC产生复开关或编码器系统的数据输入或输出显示于设备。提供的其他类型的模块也可以根据可编程序控制器(PLC)的制造商的能力而定。这些包括专业通信模块,以允许转让信息从一个控制器到另一个地方。一个新的发展是一个I/O模块允许串行传输远程I/O信息,可以到12000英尺远的地方。

4、电力供应

电源指定取决于厂商的可编程序控制器(PLC)中所使用的应用程序。如前所述,在某些情况下一分力量供应能力提供所需的电力系统布置处理模块的一部分。如果电源是一个独立的模块,它提供的电流必须能大于所需的其它模块的总和电流。系统是在CPU模块供电, 因为电压或电流的要求有一些模块的实现不可以从处理器获得过多的能量,只能通过增加第二电源，一般来说这是事实。如果模拟外部通信模块,目前由于这些要求在直流供应的情况下,在模拟模块必须进行调整。

5、编程单元

编程单位允许工程师或技术员编辑要执行的程序。编程的最简单的形式可以是一种手握设备键盘程序输入和显示设备(LED或LCD)来观看程序步骤或功能。更多的先进的系统是使用一个单独的个人电脑, 可编程序控制器(PLC)允许程序员写、查看、编辑和下载程序，这是制造商提供了从可编程序控制器(PLC) 的专有软件。该软件还可以让程序或工程师监控PLC来运行这个程序。这个监测系统,诸如可以被监控的内部线圈、寄存器、定时器和其看不见的外部来确定适当的操作。同时如果需要微调的程序操作, 可以改变内部注册数据，有利的程序可以调试。该系统可编程控制器的沟通是通过电缆连接到一个专门的编程接口控制器。这台计算机可以通过串行口或安装在一个专门的卡片连接到个人计算机。

一个可编程控制器是一个专门的计算机。因为它是一台电脑所有的基本组成部分,任何其他计算机都具有中央处理器、存储器和输入和输出接口。

中央处理器(CPU)是可编程序控制器(PLC)控制的重要部分。它可以直接从记忆和

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plc英文参考文献 PLC相关的外文英语文献与翻译

行为对那些命令解释相同的程序的命令。［www.61k.com]在当前的可编程序控制器(PLC)的这个单位是一个以微处理器为基础的系统。中央处理器(CPU)在系统模块的处理器模块。

记忆系统通常是两种类型的,只读存储器和随机存储器。ROM的记忆包含程序信息，允许中央处理器解释和行为的梯形逻辑程序存储在RAM记忆。RAM记忆通常为了不失去梯形编程系统功率的移除。这种电池可以是一个标准的干电池充电nickel-cadmium或类型。现在可更新的可编程序控制器(PLC)单位与电可擦可编程只读存储器(EEPROM)不需要电池。记忆也在模块化系统的处理器模块。

任何不同的类型的输入单位可以取决于预期的输入信号。输入一段可以接受离散的模拟信号。今天的控制器提供两种离散信号的输入交流和直流电压TTL 250 VDC,从5到250 VAC。模拟输入单位可以接受输入水平线,比如±10伏直流电、±5伏直流电和4电流环值。每CPU作为一个单一的1或0在模拟输入单元的内容模拟/数字转换电路和现在的输入电压到中央处理器，离散输入单元输入到现在以二进制规格化以最大字数数目进行传输。位的数字取决于该决议的单位，代表输入电压或电流。通常有一个定义数量的大小和数量位符号位。现在登记这个词输入单元输入到中央处理器,因为它是得到了二进制或BCD码)。

操作相同的输出单元和输入单元的除外，要么单位提供一个地或采购(提供一个电压)离散电压或采购模拟电压或电流。在输出信号的引导下,提出了中央处理器。不连续的输出电流可以为TTL和较高的直流电压或Triacs AC电压输出。为更大的电流的应用在关闭时使中间继电器接点可用。这些更大的电流一般限于2到3安培。电路输出的数字模拟的模拟模块转换生成可变电压或电流输出。

第一次使用可编程序控制器(PLC)时,它就开始了更新I/O的功能。这意味着所有离散输入状态记录从输入单元把所有离散的状态输出转移到输出单元。注册数据一般都有特定的地址和与之相关的输入输出数据，都称为输入和输出寄存器。这些调试寄存器是输入、输出模块,要求他们与离散数据一同更新。由于这是输入/输出更新,它被称为I/O更新。更新离散输入和输出信息是完成使用图像的输入和输出寄存器来搁置PLC的记忆。每一个离散输入登记相关的输入图。也就是说,每个离散输出点有一个小的输出图像登记与它联合起来。当I/O更新发生,每一个输入点,就是在那时会导致的第一个被设定的地址伴随着那个特定的输入。如果输入是关闭的,将会把一个0送到地址。今天的PLC内存中配置的通常是16位字。这意味着一个词可储存记忆的状态离散

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plc英文参考文献 PLC相关的外文英语文献与翻译

输入16。［www.61k.com）因此,有可能数量的内存留出的是图像输入与输出寄存器。I/O更新的情况是按设定输入图像登记的离散状态，从输入和输出的图像状态寄存器转移到输出单元。通常只有传输信息发生时在I/O更新。它可能被迫发生在其他可编程序控制器(PLC)的时代有很明显的I/O更新的命令。这个命令在其他时候将迫使PLC更新I/O,尽管这是一个特殊例子。

在研究的开始,PLC编程可以是很重要的一个模块。获得了解各种类型的plc,以及可编程序控制器(PLC)怎样执行一个程序。开放的框架和模块化的plc都适合在特定类型的基础上的应用环境条件,数量的输入和输出的扩张和进入监控程序。此外,编程需要优先接收输入信息、执行PLC程序,并输出信息。根据这些信息,我们开始研究PLC程序设计。

当写程序时,梯形图控制机器。其原因是,在一个基本的标准的逻辑plc程序是非常相似的电气图，这不是巧合。工程师们对发展PLC编程语言很敏感，大多数工程师、技术员和电工电气机械工作人员每天将熟悉这种方法的控制逻辑,代表这将允许更新,只有熟悉plc控制图,能够适应非常迅速的编程语言。PLC编程语言是一个最简单的编程语言学习。

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扩展：plc外文文献及翻译 / plc外文文献翻译 / 英语专业外文文献翻译

三 : JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

THE TECHNIQUE DEVELOPMENT HISTORY OF JSP

By:Kathy Sierra and Bert Bates

Source: Servlet&JSP

1.1 GENERALIZE

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

JSP provides the following benefits over servlets alone:

? It is easier to write and maintain the HTML. Your static code is ordinary HTML: no extra backslashes, no double quotes, and no lurking Java syntax.

? You can use standard Web-site development tools. Even HTML tools that know nothing about JSP can be used because they simply ignore the JSP tags.

1.2 SOURCE OF JSP

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

to the each claimses, and make use of the multi-threading mechanism can at the same time for several claim service, therefore the efficiency of Java Servlet is very high.

1.3JSP CHARACTERISTICS

Is a service according to the script language in some one language of the statures system this kind of discuss, the JSP should be see make is a kind of script language. 3

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

However, be a kind of script language, the JSP seemed to be too strong again, almost can use all Javas in the JSP.

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

1.4JSP MECHANISM

The SSJS and ASP are all in several year ago to release, the network of that time is still very young, no one knows to still have in addition to making all business, datas and the 4

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

JSP的技术发展历史

作者： Kathy Sierra and Bert Bates

来源： Servlet&JSP

Java Server Pages(JSP)是一种基于web的脚本编程技术，类似于网景公司的服务器端Java脚本语言—— server-side JavaScript(SSJS)和微软的Active Server Pages(ASP)。［www.61k.com]与SSJS和ASP相比，JSP具有更好的可扩展性，并且它不专属于任何一家厂商或某一特定的Web服务器。尽管JSP规范是由Sun公司制定的，但任何厂商都可以在自己的系统上实现JSP。

1.1 概述

和单独使用servlet相比，JSP提供下述好处：

JSP中HTML的编写与维护更为简单。JSP中可以使用常规的HTML：没有额外的反斜杠，没有额外的双引号，也没有暗含的Java语法。

能够使用标准的网站开发工具。即使是那些对JSP一无所知的HTML工具，我们也可以使用，因为它们会忽略JSP标签（JSP tags）。

可以对开发团队进行划分。Java程序员可以致力于动态代码。Web开发人员可以将 7

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

经理集中在表示层（presentation layer）上。(www.61k.com］对于大型的项目，这种划分极为重要。依据开发团队的大小，及项目的复杂程度，可以对静态HTML和动态内容进行弱分离（weaker separation）和强分离（stronger separation）。

1.2 JSP的由来

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

将页面设计成由静态HTML和用特殊标签标记的动态代码混合组成.。［www.61k.com］ColdFusion多年前就已经这样做了。甚至ASP(来自于前述经理所在公司的一项产品)都在JSP出现之前推广了这种方式。实际上,JSP不只采用了这种通用概念,它甚至使用许多和ASP相同的特殊标签。

1.3 JSP的特点

1.4 JSP的机制

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

为中心的模型容易学习并且得到相当快速的发展。（www.61k.com］然而，随着时间的推移，人们认识到这种方法不适于构建大型的、可升级的Web应用程序。在脚本环境中书写的表达逻辑被锁在页面内，只有通过剪切和粘贴才能被重用。表达逻辑通常和商务及数据逻辑混在一起，这使得当程序员试图改变一个应用程序的外观而不想破坏与之紧密结合的商务逻辑时，应用程序的维护就变得十分艰难。其事实上，企业中可重用组件的应用早已经很成熟，没有人愿意为它们的应用程序重写那些逻辑。HTML和图形设计师把它们的设计的实施工作交给了Web编写者，使他们不得不加倍工作—— 常常是手工编写，因为没有合适的工具可以把服务器端脚本与HTML内容结合起来。简而言之，随着Web应用程序的复杂性不断提升，以页面为中心的开发方式的局限性变得明显起来。

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

jsp英文参考文献 JSP的技术发展-中英文文献翻译

河南理工大学毕业设计（论文）外文翻译

对于作为Web服务器的计算机将是不小的负担。(www.61k.com)其次，JSP是专门为Web开发而设计的，其目的是为了建立基于Web的应用程序，其中包含了一整套的规范和工具。使用JSP技术可以很方便地将一大堆JSP页面组合成为一个Web应用程序。

扩展：jsp中英文文献 / 中英文文献翻译 / ios中英文翻译文献

本文标题：专利文献的英汉翻译-JSP的技术发展-中英文文献翻译
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