JSP的技術(shù)發(fā)展歷史

1、精品好資料學(xué)習(xí)推薦THE TECHNIQUE DEVELOPMENT HISTORY OF JSPBy:Kathy Sierra and Bert BatesSource:Servlet&JSPThe 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 JavaScr

2、ipt( 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

3、 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 peoples concern.JSP provided a special development environment for the Web application that establishes the high dynamic state.According

4、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 per

5、haps to is a Guide only, if the reader needs the more detailed information, pleasing the book of consult the homologous JSP.1.1 GENER ALIZEThe 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

6、 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

7、 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. Howe

8、ver, 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 pla

9、tform in the Java programming language you could also do in assembly language. But it still matters which you choose.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

10、 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 th

11、e 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 usi

12、ng 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 apGFDGpropriate tool for the job, and servlet

13、s, by themselves, do not complete your toolkit.1.2 SOURCE OF JSPThe 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 becom

14、es 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 com

15、es 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 dont 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.

16、 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 ter

17、race 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 i

18、rrelevant, 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 to the each claimses,

19、 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

20、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 rel

21、eased 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 la

22、rge 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

23、excellent idea. He went on to say that theywould keep an eye on it, and if it seemed to be catching on, they would follow his companys usual embrace and extend strategy. At this point, Gosling lightheartedly interjected You mean disgrace and distend. Now, the grievance that Gosling was airing was th

24、at 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 ex

25、ample, ColdFusion 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 a

26、s 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 stat

27、e 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 CHARACTERISTICSIs a service according to the script language in some one langua

28、ge of the statures system this kind of discuss, the JSP should be see make is a kind of script language.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 de

29、velopment 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 th

30、e 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

31、 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 Serv

32、let 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

33、etc., because speed etc. reason, have already cant 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 JS

34、P 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 ou

35、t 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

36、performance code also should is related with Java.1.4JSP MECHANISMTo 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 t

37、he page develops for the web page of the center first. The SSJS and ASP are all in several year agoto 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 expression logic enter the original web page entirely heap what be

38、tter 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

39、 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 proced

40、ure 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

41、 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

42、 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 app

43、lication procedure, the module spreads in customers 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( RA

44、D) 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 ter

45、race, 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 prese

46、nt 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

47、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. See now how JSP is handle claim of HTTP.In basic claim model, a claim directly was send to JSP page in.The cod

48、e 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 cl

49、aim 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 p

50、iece 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 ac

51、tual 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 tran

52、slate 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

53、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 p

54、age 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 JS

55、P 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.JSP的技術(shù)發(fā)展歷史作者：

56、 Kathy Sierra and Bert Bates來(lái)源： Servlet&JSPJava Server Pages(JSP)是一種基于web的腳本編程技術(shù)，類似于網(wǎng)景公司的服務(wù)器端Java腳本語(yǔ)言server-side JavaScript(SSJS)和微軟的Active Server Pages(ASP)。與SSJS和ASP相比，JSP具有更好的可擴(kuò)展性，并且它不專屬于任何一家廠商或某一特定的Web服務(wù)器。盡管JSP規(guī)范是由Sun公司制定的，但任何廠商都可以在自己的系統(tǒng)上實(shí)現(xiàn)JSP。 在Sun正式發(fā)布JSP(Java Server Pages)之后，這種新的Web應(yīng)用開(kāi)發(fā)技術(shù)很快引起了

57、人們的關(guān)注。JSP為創(chuàng)建高度動(dòng)態(tài)的Web應(yīng)用提供了一個(gè)獨(dú)特的開(kāi)發(fā)環(huán)境。按照Sun的說(shuō)法，JSP能夠適應(yīng)市場(chǎng)上包括Apache WebServer、IIS4.0在內(nèi)的85%的服務(wù)器產(chǎn)品。本文將介紹JSP相關(guān)的知識(shí)，以及JavaBean的相關(guān)內(nèi)容，當(dāng)然都是比較粗略的介紹其中的基本內(nèi)容，僅僅起到拋磚引玉的作用，如果讀者需要更詳細(xì)的信息，請(qǐng)參考相應(yīng)的JSP的書籍。1.1 概述JSP(Java Server Pages)是由Sun Microsystems公司倡導(dǎo)、許多公司參與一起建立的一種動(dòng)態(tài)網(wǎng)頁(yè)技術(shù)標(biāo)準(zhǔn)，其在動(dòng)態(tài)網(wǎng)頁(yè)的建設(shè)中有其強(qiáng)大而特別的功能。JSP與Microsoft的ASP技術(shù)非常相似。兩者都

58、提供在HTML代碼中混合某種程序代碼、由語(yǔ)言引擎解釋執(zhí)行程序代碼的能力。下面我們簡(jiǎn)單的對(duì)它進(jìn)行介紹。JSP頁(yè)面最終會(huì)轉(zhuǎn)換成servlet。因而，從根本上，JSP頁(yè)面能夠執(zhí)行的任何任務(wù)都可以用servlet來(lái)完成。然而，這種底層的等同性并不意味著servlet和JSP頁(yè)面對(duì)于所有的情況都等同適用。問(wèn)題不在于技術(shù)的能力，而是二者在便利性、生產(chǎn)率和可維護(hù)性上的不同。畢竟，在特定平臺(tái)上能夠用Java編程語(yǔ)言完成的事情，同樣可以用匯編語(yǔ)言來(lái)完成，但是選擇哪種語(yǔ)言依舊十分重要。和單獨(dú)使用servlet相比，JSP提供下述好處：JSP中HTML的編寫與維護(hù)更為簡(jiǎn)單。JSP中可以使用常規(guī)的HTML：沒(méi)有額外的

59、反斜杠，沒(méi)有額外的雙引號(hào)，也沒(méi)有暗含的Java語(yǔ)法。能夠使用標(biāo)準(zhǔn)的網(wǎng)站開(kāi)發(fā)工具。即使是那些對(duì)JSP一無(wú)所知的HTML工具，我們也可以使用，因?yàn)樗鼈儠?huì)忽略JSP標(biāo)簽（JSP tags）?？梢詫?duì)開(kāi)發(fā)團(tuán)隊(duì)進(jìn)行劃分。Java程序員可以致力于動(dòng)態(tài)代碼。Web開(kāi)發(fā)人員可以將經(jīng)理集中在表示層（presentation layer）上。對(duì)于大型的項(xiàng)目，這種劃分極為重要。依據(jù)開(kāi)發(fā)團(tuán)隊(duì)的大小，及項(xiàng)目的復(fù)雜程度，可以對(duì)靜態(tài)HTML和動(dòng)態(tài)內(nèi)容進(jìn)行弱分離（weaker separation）和強(qiáng)分離（stronger separation）。此處的討論并不是說(shuō)人們應(yīng)該放棄使用servlet而僅僅使用JSP。事實(shí)上，幾乎所有的項(xiàng)目都會(huì)同時(shí)用到這兩種技術(shù)。在某些項(xiàng)目中，更適宜選用servlet，而針對(duì)項(xiàng)目中的某些請(qǐng)求，我們可能會(huì)在MVC構(gòu)架下組合使用這兩項(xiàng)技術(shù)。我們總是希望用適當(dāng)?shù)墓ぞ咄瓿上鄬?duì)應(yīng)的工作，僅僅是servlet并不一定能夠勝任所有工作。1.2 JSP的由來(lái)Sun公