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1、毕业设计说明书英文文献及中文翻译班 级： 学号： 姓 名： 学 院： 专 业： 指导教师： 年 月JSP Technology Conspectus And SpecialtiesThe JSP (Java Server mix) technology is used by the Sun microsystem issued by the company to develop dynamic Web application technology. With its easy, cross-platform, in many dynamic Web application programmin
2、g 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. The related technologies of JSP are brie
3、fly 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 easier and efficient, and these applications a
4、nd 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 technology, such as CGI, ASP, etc. With the
5、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 transactions evolution to acquisition of an op
6、eration 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 almost no limit client access and extremely
7、 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 client browser multi-layer application.The rapid
8、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 content of a Web page is based on the users
9、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 the Web server to invoke the former. This
10、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 be reduced to extremely low.Some Web serve
11、r 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 Server mix (ASP) technology in the Web page to c
12、reate 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 language interaction application server code easie
13、r. 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: one is based on a Java Servlet Java technica
14、l 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, youll have to edit and recompile the Servlet Ja
15、va, 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. This program will solve the current scheme are
16、 limited. As follows: can on any Web server or applications.will application page displays and separation. can rapidly developing and testing. simplify the interactive development based on Web application process.The JSP technology is designed to meet such requirements. The JSP specification is a We
17、b server, application server, trading system and develop 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 JavaBeans) support techniques and tools. The result is a kind o
18、f 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 _jspService() method mapping from the request to the response object. Some details of this tr
19、ansformation 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 into the output stream of the response. (The JSP con
20、tainer usually sends this data back to the client.) The description is based on a JspWriter 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 JspWriter object. This object may be different from the stream obje
21、ct returned from response.getWriter(), 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 writing directly to either the PrintWriter or OutputStream
22、associated with the ServletResponse.The JSP container should not invoke response.getWriter() 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 language to “glue” actions that deliver binary content, or rel
23、iably 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 different (nested) instance of a JspWriter object. Whether this i
24、s 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) stream. Such nested streams are always buffered, and require ex
25、plicit flushing to a nesting stream or their contents will be discarded.If the initial out JspWriter object is buffered, then depending upon the value of the autoFlush attribute of the page directive, the content of that buffer will either be automatically flushed out to the ServletResponse output s
26、tream to obviate overflow, or an exception shall be thrown to signal buffer overflow. If the initial out JspWriter is unbuffered, then content written to it will be passed directly through to the ServletResponse output stream.A JSP page can also describe what should happen when some specific events
27、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 kind is browser, the dynamic general purpose of client scripting langua
28、ge. Netscape first proposed in 1995, but its JavaScript LiveScript called. Then quickly Netscape LiveScript renamed JavaScript, Java developers with them from the same issued a statement. A statement Java and JavaScript will complement each other, but they are different, so the technology of the man
29、y 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 cursor on the Web page of a mobile user input validation or transform image
30、.Microsoft also write out their JavaScript version and the JScript called. Microsoft and Netscape support JavaScript and JScript around a core characteristics and European Manufacturers is.md by (ECMA) standards organization, the control standard of scripting language. ECMA its scripting language EC
31、MAScript named.Servlets and JSPs 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 the information wherever it is needed, since it is easier to change content
32、 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 and changes often and unpredictably, such as a textual greeting that must b
33、e 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 as necessary.You want to include a resource that does not change very much (s
34、uch 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 .jspf extension.You want to include content in a JSP each time it receives a request, rather than when the JSP is converted to a servlet. Use
35、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 a configuration parameter in the deployment descriptor.You want to include
36、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.include element if the include action should occur during the translation phase.You
37、 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 strengths.For the first time in a JSP documents requested by the engine, JSP Servle
38、t 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 have any grammar mistake JSP, conversion process will interrupt, and to the server
39、and client output error messages.(2) if converted, with the engine JSP javac Java source file compiler into a corresponding scale-up files.(3) to create a the Servlet (JSP page), the transformation of the Servlet jspInit () method was executed, jspInit () method in the life cycle of Servlet executed
40、 only once.(4) jspService () 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 create multiple threads. Each client requests a thread. To execute multi-thre
41、ad 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 very fast.(5) if the file has been modified. The JSP, server will be set a
42、ccording 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 and compile and some slight delay. In addition, if at any time due to rea
43、sons of system resources, JSP engine will in some way of uncertain Servlet will remove from memory. When this happens jspDestroy () method was first call.(7) and then Servlet examples were marked with add garbage collection. But in jspInit () some initialization work, if establish connection with da
44、tabase, or to establish a network connection, from a configuration file take some parameters, such as, in jspDestory () release of the corresponding resources.JSP技术简介及特点JSP（Java Server Pages）技术是由Sun公司发布的用于开发动态Web应用的一项技术。它以其简单易学、跨平台的特性，在众多动态Web应用程序设计语言中异军突起，在短短几年中已经形成了一套完整的规范，并广泛地应用于电子商务等各个领域中。在国内，JS
45、P现在也得到了比较广泛的重视，得到了很好的发展，越来越多的动态网站开始采用JSP技术。下面就对JSP及其相关技术进行简单的介绍。JSP技术可以以一种简捷而快速的方法生成Web页面。使用JSP技术的Web页面可以很容易地显示动态内容。JSP技术的设计目的是使得构造基于Web的应用程序更加容易和快捷，而这些应用程序能够与各种Web服务器、应用服务器、浏览器和开发工具共同工作。JSP技术不是惟一的动态网页技术，也不是第一个，在JSP技术出现之前就已经存在几种优秀的动态网页技术，如CGI、ASP等。下面结合这些技术的介绍，讲述动态网页技术的发展和JSP技术的诞生。JSP的开发背景及发展历史在万维网短暂
46、的历史中，万维网已经从一个大部分显示静态信息的网络演化到对股票进行交易和进行购书操作的一个基础设施。在各种各样的应用程序中，对于可能使用的基于Web的客户端，看上去没有任何限制。基于浏览器客户端的应用程序比传统的基于客户机/服务器的应用程序有几个好处。这些好处包括几乎没有限制的客户端访问和极其简化的应用程序部署和管理（要更新一个应用程序，管理人员只需要更改一个基于服务器的程序，而不是成千上万的安装在客户端的应用程序）。这样，软件工业正迅速地向建造基于浏览器客户端的多层次应用程序迈进。这些快速增长的精巧的基于Web的应用程序要求开发技术上的改进。静态HTML对于显示相对静态的内容是不错的选择；新
47、的挑战在于创建交互的基于Web的应用程序，在这些程序中，页面的内容是基于用户的请求或者系统的状态，而不是预先定义的文字。对于这个问题的一个早期解决方案是使用CGI-BIN接口。开发人员编写与接口相关的单独的程序，以及基于Web的应用程序，后者通过Web服务器来调用前者。这个方案有着严重的扩展性问题每个新的CGI要求在服务器上新增一个进程。如果多个用户并发地访问该程序，这些进程将消耗该Web服务器所有的可用资源，并且系统性能会降低到极其低下的地步。某些Web服务器供应商已经尝试通过为他们的服务器提供“插件”和API来简化Web应用程序的开发。这些解决方案是与特定的Web服务器相关的，不能解决跨多
48、个供应商的解决方案的问题。例如，微软的Active Server Pages（ASP）技术使得在Web页面上创建动态内容更加容易，但也只能工作在微软的IIS和Personal Web Server上。还存在其他的解决方案，但都不能使一个普通的页面设计者能够轻易地掌握。例如，像Java Servlet这样的技术就可以使得用Java语言编写交互的应用程序的服务器端的代码变得容易。开发人员能够编写出这样的Servlet，以接收来自Web浏览器的HTTP请求，动态地生成响应（可能要查询数据库来完成这项请求），然后发送包含HTML或XML文档的响应到浏览器。注意：一个Java Servlet就是一个基于Java技术的运行在服务器端的程序（与Applet不同，后者运行在浏览器端）。Servlet会在本书第4章介绍。采用这种方法，整个网页必须都在Java Servlet中制作。如果开发人员或者Web管理人员想要调整页面显示，就不得不编辑并重新编译该Java Servlet，即使在逻辑上已经能够运行了。采用这种方法，生成带有动态内容的页面仍然需要应用程序的开发技巧。很显然，目前所需要的是一个业界范围内的创建动态内容页面的解决方案。这个方案将解决当前方案所受到的限制。如下：1) 能够在任何Web或应用程序服务器上运行。2) 将应用程序逻辑和页面显示分离。3)
