《毕业论文外文翻译-JSP技术简介及特点.doc》由会员分享，可在线阅读，更多相关《毕业论文外文翻译-JSP技术简介及特点.doc（24页珍藏版）》请在taowenge.com淘文阁网|工程机械CAD图纸|机械工程制图|CAD装配图下载|SolidWorks_CaTia_CAD_UG_PROE_设计图分享下载上搜索。
1、专业外文翻译题 目JSP Technology Conspectus and Specialties系 （院）计算机系专 业计算机科学与技术班 级学生姓名学 号指导教师职 称 JSP Technology Conspectus and SpecialtiesThe JSP (Java Server Pages) technology is used by the Sun micro-system issued by the company to develop dynamic Web application technology. With its easy, cross-platform,
2、in many dynamic Web application programming languages, in a short span of a few years, has formed a complete set of standards, and widely used in electronic commerce, etc. In China, the JSP now also got more extensive attention; get a good development, more and more dynamic website to JSP technology
3、. The related technologies of JSP are briefly introduced.The JSP a simple technology can quickly and with the method of generating Web pages. Use the JSP technology Web page can be easily display dynamic content. The JSP technology are designed to make the construction based on Web applications easi
4、er and efficient, and these applications and various Web server, application server, the browser and development tools work together.The JSP technology isnt the only dynamic web technology, also not the first one, in the JSP technology existed before the emergence of several excellent dynamic web te
5、chnologies, such as CGI, ASP, etc. With the introduction of these technologies under dynamic web technology, the development and the JSP. TechnicalJSP the development background and development historyIn web brief history, from a world wide web that most of the network information static on stock tr
6、ansactions evolution to acquisition of an operation and infrastructure. In a variety of applications, may be used for based on Web client, look no restrictions.Based on the browser client applications than traditional based on client/server applications has several advantages. These benefits include
7、 almost no limit client access and extremely simplified application deployment and management (to update an application, management personnel only need to change the program on a server, not thousands of installation in client applications). So, the software industry is rapidly to build on the clien
8、t browser multilayer application.The rapid growth of exquisite based Web application requirements development of technical improvements. Static HTML to show relatively static content is right choice, the new challenge is to create the interaction based on Web applications, in these procedures, the c
9、ontent of a Web page is based on the users request or the state of the system, and are not predefined characters.For the problem of an early solution is to use a CGI - BIN interface. Developers write to interface with the relevant procedures and separate based on Web applications, the latter through
10、 the Web server to invoke the former. This plan has serious problem - each new extensible CGI requirements in a new process on the server. If multiple concurrent users access to this procedure, these processes will use the Web server of all available resources, and the performance of the system will
11、 be reduced to extremely low.Some Web server providers have to provide for their server by plugins and the API to simplify the Web application development. These solutions are associated with certain Web server, cannot solve the span multiple suppliers solutions. For example, Microsofts Active Serve
12、r mix (ASP) technology in the Web page to create dynamic content more easily, but also can work in Microsoft on Personal Web Server and IIS.There are other solutions, but cannot make an ordinary page designers can easily master. For example, such as the Servlet Java technologies can use Java languag
13、e interaction application server code easier. Developers to write such Servlet to receive signals from the Web browser to generate an HTTP request, a dynamic response (may be inquires the database to finish the request), then send contain HTML or XML documents to the response of the browser.% Note:
14、one is based on a Java Servlet Java technical operation in the server program (with different, the latter operating in the Applet browser end). In this book the Servlet chapter 4.Using this method, the entire page must have made in Java Servlet. If developers or Web managers want to adjust page, you
15、ll have to edit and recompile the Servlet Java, even in logic has been able to run. Using this method, the dynamic content with the application of the page still need to develop skills.Obviously, what is needed is a industry to create dynamic content within the scope of the pages of the solution. Th
16、is program will solve the current scheme are limited. As follows:q can on any Web server or applications.q will application page displays and separation.q can rapidly developing and testing.q simplify the interactive development based on Web application process.The JSP technology is designed to meet
17、 such requirements. The JSP specification is a Web server, application server, trading system and develops extensive cooperation between the tool suppliers. From this standard to develop the existing integration and balance of Java programming environment (for example, Java Servlet and Java Beans) s
18、upport techniques and tools. The result is a kind of new and developing method based on Web applications, using component-based application logic page designers with powerful functions.Overall Semantics of a JSP PageA JSP page implementation class defines a JSP Service () method mapping from the req
19、uest to the response object. Some details of this transformation are specific to the scripting language used (see Chapter JSP.9, “Scripting”). Most details are not language specific and are described in this chapter.The content of a JSP page is devoted largely to describing the data that is written
20、into the output stream of the response. (The JSP container usually sends this data back to the client.) The description is based on a JSP Writer object that is exposed through the implicit object out (see Section JSP.1.8.3, “Implicit Objects”). Its value varies:Initially, out is a new JSP Writer obj
21、ect. This object may be different from the stream object returned from response, get Writer (), and may be considered to be interposed on the latter in order to implement buffering (see Section JSP.1.10.1, “The page Directive”). This is the initial out object. JSP page authors are prohibited from wr
22、iting directly to either the Print Writer or Output Stream associated with the Servlet Response.The JSP container should not invoke response.get Writer () until the time when the first portion of the content is to be sent to the client. This enables a number of uses of JSP, including using JSP as a
23、language to “glue” actions that deliver binary content, or reliably forwarding to a Servlet, or change dynamically the content type of the response before generating content. See Chapter JSP.4, “Internationalization Issues”.Within the body of some actions, out may be temporarily re-assigned to a dif
24、ferent (nested) instance of a JSP Writer object. Whether this is the case depends on the details of the actions semantics. Typically the content of these temporary streams is appended to the stream previously referred to by out, and out is subsequently re-assigned to refer to the previous (nesting)
25、stream. Such nested streams are always buffered, and require explicit flushing to a nesting stream or their contents will be discarded.If the initial out JSP Writer object is buffered, then depending upon the value of the auto-Flush attribute of the page directive, the content of that buffer will ei
26、ther be automatically flushed out to the Servlet Response output stream to obviate overflow, or an exception shall be thrown to signal buffer overflow. If the initial out JSP Writer is unbuffered, then content written to it will be passed directly through to the Servlet Response output stream.A JSP
27、page can also describe what should happen when some specific events occur. In JSP 2.1, the only events that can be described are the initialization and the destruction of the page. These events are described using “well-known method names” in declaration elements.JavaScript is used for the first kin
28、d is browser, the dynamic general purpose of client scripting language. Netscape first proposed in 1995, but its JavaScript Live Script called. Then quickly Netscape Live Script renamed JavaScript, Java developers with them from the same issued a statement. A statement Java and JavaScript will compl
29、ement each other, but they are different, so the technology of the many dismissed the misunderstanding of the two technologies.JavaScript to create user interface control provides a scripting language. In fact, in the browser into the JavaScript code logic. It can support such effect: when the curso
30、r on the Web page of a mobile user input validation or transform image.Microsoft also writes out their JavaScript version and the JSP script called. Microsoft and Netscape support JavaScript and JSP script around core characteristics and European Manufacturers is made by (ECMA) standards organizatio
31、n, the control standard of scripting language. ECMA its scripting language ECMAScript named.Servlets and JSP often include fragments of information that are common to an organization, such as logos, copyrights, trademarks, or navigation bars. The web application uses the include mechanisms to import
32、 the information wherever it is needed, since it is easier to change content in one place then to maintain it in every piece of code where it is used. Some of this information is static and either never or rarely changes, such as an organizations logo. In other cases, the information is more dynamic
33、 and changes often and unpredictably, such as a textual greeting that must be localized for each user. In both cases, you want to ensure that the servlet or JSP can evolve independently of its included content, and that the implementation of the servlet or JSP properly updates its included content a
34、s necessary.You want to include a resource that does not change very much (such as a page fragment that represents a header or footer) in a JSP. Use the include directive in the including JSP page, and give the included JSP segment a JSP extension.You want to include content in a JSP each time it re
35、ceives a request, rather than when the JSP is converted to a servlet. Use the JSP: include standard action.You want to include a file dynamically in a JSP, based on a value derived from a configuration file. Use the JSP: include standard action. Provide the value in an external properties file or as
36、 a configuration parameter in the deployment descriptor.You want to include a fragment of an XML file inside of a JSP document, or include a JSP page in XML syntax. Use the JSP: include standard action for the includes that you want to occur with each request of the JSP. Use the JSP: directive.inclu
37、de element if the includes action should occur during the translation phase.You want to include a JSP segment from outside the including files context. Use the c: importThe operation principle and the advantages of JSP tagsIn this section of the operating principle of simple introduction JSP and str
38、engths.For the first time in a JSP documents requested by the engine, JSP Servlet is transformed into a document JSP. This engine is itself a Servlet. The operating process of the JSP shown below:(1) The JSP engine put the JSP files converting a Java source files (Servlet), if you find the files hav
39、e any grammar mistake JSP, conversion process will interrupt, and to the server and client output error messages.(2) If converted, with the engine JSP Java source file compiler into a corresponding scale-up files.(3) To create a Servlet (JSP page), the transformation of the Servlet JSP Init () metho
40、d was executed, JSP Init () method in the life cycle of Servlet executed only once.(4) JSP Service () method invocation to the client requests. For each request, JSP engine to create a new thread for processing the request. If you have multiple clients and request the JSP files, JSP engine will crea
41、te multiple threads. Each client requests a thread. To execute multi-thread can greatly reduce the requirement of system resources, improving the concurrency value and response time. But also should notice the multi-thread programming, due to the limited Servlet always in response to memory, so is v
42、ery fast.(5) If the file has been modified. The JSP, server will be set according to the document to decide whether to recompile, if need to recompile, will replace the Servlet compile the memory and continue the process.(6) Although the JSP efficiency is high, but at first when the need to convert
43、and compile and some slight delay. In addition, if at any time due to reasons of system resources, JSP engine will in some way of uncertain Servlet will remove from memory. When this happens JSP Destroy () method was first call.(7) And then Servlet examples were marked with add garbage collection. B
44、ut in JSP Init () some initialization work, if establish connection with database, or to establish a network connection, from a configuration file take some parameters, such as, in JSP Destroy () release of the corresponding resources.Based on a Java language has many other techniques JSP page dynam
45、ic characteristics, technical have embodied in the following aspects:One. Simplicity and effectivenessThe JSP dynamic web pages with the compilation of the static HTML pages of writing are very similar. Just in the original HTML page add JSP tags, or some of the proprietary scripting (this is not ne
46、cessary). So, a familiar with HTML page write design personnel may be easily performed JSP page development. And the developers can not only, and write script by JSP tags used exclusively others have written parts to realize dynamic pages. So, an unfamiliar with the web developers scripting language
47、, can use the JSP make beautiful dynamic pages. And this in other dynamic web development is impossible.Tow. The independence of the programThe JSP are part of the family of the API Java, it has the general characteristics of the cross-platform Java program. In other words, is to have the procedure,
48、 namely the independence of the platform, 6 Write bid anywhere! .Three. Procedures compatibilityThe dynamic content can various JSP form, so it can show for all kinds of customers, namely from using HTML/DHTML browser to use various handheld wireless equipment WML (for example, mobile phones and PDA
49、), personal digital equipment to use XML applications, all can use B2B JSP dynamic pages.Four. Program reusabilityIn the JSP page can not directly, but embedded scripting dynamic interaction will be cited as a component part. So, once such a component to write, it can be repeated several procedures, the program of the reusability. Now, a lot of standard Java Beans library is a good example.JSP te