1、外文资料原文 JSP Technology Conspectus And Specialties Thomas R Rohleder The 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 programming languages, in a short
2、 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 briefly introduced. The JSP
3、 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 and various Web server,
4、 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 introduction of these
5、 technologies under dynamic web technology, the development and the JSP. Technical JSP the development background and development history In web brief history, from a world wide web that most of the network information static on stock transactions evolution to acquisition of an operation and infrast
6、ructure. 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 simplified applic
7、ation 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 growth of exquisi
8、te 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 request or the st
9、ate 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 plan has serious
10、 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 server providers hav
11、e 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 create dynamic c
12、ontent 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 easier. Developers
13、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 technical operation in
14、 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 Java, even in l
15、ogic 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 limited. As
16、 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 Web server,
17、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 of new and
18、developing method based on Web applications, using component-based application logic page designers with powerful functions. Overall Semantics of a JSP Page A JSP page implementation class defines a _jspService() method mapping from the request to the response object. Some details of this transforma
19、tion 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 container
20、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 object ret
21、urned 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 associ
22、ated 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 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 different
