外文翻译-----JSP简介

JSP

Open Category: WEB, JAVA, dynamic pages, the Knowledge Network

Contents ? JSP Profile

? JSP technology strength ? JSP technology vulnerable ? JSP six built-in objects:

? JSP dynamic web site development and technology

JSP Profile

JSP (JavaServer Pages) is initiated by Sun Microsystems, Inc., with many companies to participate in the establishment of a dynamic web page technical standards. JSP technology somewhat similar to ASP technology, it is in the traditional HTML web page document (*. htm, *. html) to insert the Java programming paragraph (Scriptlet) and JSP tag (tag), thus JSP documents (*. jsp).

Using JSP development of the Web application is cross-platform that can run on Linux, is also available for other operating systems.

JSP technology to use the Java programming language prepared by the category of XML tags and scriptlets, to produce dynamic pages package processing logic. Page also visit by tags and scriptlets exist in the services side of the resources of logic. JSP page logic and web page design and display separation, support reusable component-based design, Web-based application development is rapid and easy.

Web server in the face of visits JSP page request, the first implementation of the

procedures of, and then together with the results of the implementation of JSP documents in HTML code with the return to the customer. Insert the Java programming operation of the database can be re-oriented websites, in order to achieve the establishment of dynamic pages needed to function.

JSP and Java Servlet, is in the implementation of the server, usually returned to the client is an HTML text, as long as the client browser will be able to visit.

JSP 1.0 specification of the final version is launched in September 1999, December has introduced 1.1 specifications. At present relatively new is JSP1.2 norms, JSP2.0 norms of the draft has also been introduced.

JSP pages from HTML code and Java code embedded in one of the components. The server was in the pages of client requests after the Java code and then will generate the HTML pages to return to the client browser. Java Servlet JSP is the technical foundation and large-scale Web application development needs of Java Servlet and JSP support to complete. JSP with the Java technology easy to use, fully object-oriented, and a platform-independent and secure, mainly for all the characteristics of the Internet.

JSP technology strength

(1) time to prepare, run everywhere. At this point Java better than PHP, in addition to systems, the code not to make any changes.

(2) the multi-platform support. Basically on all platforms of any development environment, in any environment for deployment in any environment in the expansion. Compared ASP / PHP limitations are obvious.

(3) a strong scalability. From only a small Jar documents can run Servlet / JSP, to the multiple servers clustering and load balancing, to multiple Application for transaction processing, information processing, a server to numerous servers, Java shows a tremendous Vitality.

(4) diversification and powerful development tools support. This is similar to the ASP, Java already have many very good development tools, and many can be free, and many of them have been able to run on a variety of platforms under.

JSP technology vulnerable

(1) and the same ASP, Java is the advantage of some of its fatal problem. It is precisely because in order to cross-platform functionality, in order to extreme stretching capacity, greatly increasing the complexity of the product.

(2) Java's speed is class to complete the permanent memory, so in some cases by the use of memory compared to the number of users is indeed a \performance.\documents and. Class, as well as the corresponding versions of documents.

JSP six built-in objects:

request, response, out, session, application, config, pagecontext, page, exception. 1. Request for:

The object of the package of information submitted by users, by calling the object corresponding way to access the information package, namely the use of the target users can access the information. 2. Response object:

The customer's request dynamic response to the client sent the data. 三. session object

1. What is the session: session object is a built-in objects JSP, it in the first JSP pages loaded automatically create, complete the conversation of management.

From a customer to open a browser and connect to the server, to close the browser, leaving the end of this server, known as a conversation. When a customer visits a server, the server may be a few pages link between repeatedly, repeatedly refresh a page, the server should be through some kind of way to know this is the same client, which requires session object.

2. session object ID: When a customer's first visit to a server on the JSP pages, JSP engines produce a session object, and assigned a String type of ID number, JSP engine at the same time, the ID number sent to the client, stored in Cookie, this session objects, and customers on the establishment of a one-to-one relationship. When a customer to connect to the server of the other pages, customers no longer allocated to the new session object, until, close your browser, the client-server object to cancel the session, and the conversation, and customer relationship disappeared. When a customer re-open the browser to connect to the server, the server for the customer to create a new session object.

四. aplication target 1. What is the application:

Servers have launched after the application object, when a customer to visit the site between the various pages here, this application objects are the same, until the server is down. But with the session difference is that all customers of the application objects are the same, that is, all customers share this built-in application objects. 2. application objects commonly used methods:

(1) public void setAttribute (String key, Object obj): Object specified parameters will be the object obj added to the application object, and to add the subject of the designation of a keyword index.

(2) public Object getAttribute (String key): access to application objects containing keywords for. 五. out targets

out as a target output flow, used to client output data. out targets for the output data. 六. Cookie 1. What is Cookie:

Cookie is stored in Web server on the user's hard drive section of the text. Cookie allow a Web site on the user's computer to store information on and then get back to it. For example, a Web site may be generated for each visitor a unique ID, and then to Cookie in the form of documents stored in each user's machine.

If you use IE browser to visit Web, you will see all stored on your hard drive on the Cookie. They are most often stored in places: c: \\ windows \\ cookies (in Window2000 is in the C: \\ Documents and Settings \\ your user name \\ Cookies)

Cookie is \ 2. Targets the creation of a Cookie, Cookie object called the constructor can create a Cookie. Cookie object constructor has two string parameters: Cookie Cookie name and value.

Cookie c = new Cookie ( \

3. If the JSP in the package good Cookie object to send to the client, the use of the response addCookie () method. Format: response.addCookie (c)

4. Save to read the client's Cookie, the use of the object request getCookies () method will be implemented in all client came to an array of Cookie objects in the form of order, to meet the need to remove the Cookie object, it is necessary to compare an array cycle Each target keywords. JSP简介

JSP(JavaServer 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。JSP技术有点类似ASP技术，它是在传统的网页HTML文件

(*.htm,*.html)中插入Java程序段(Scriptlet)和JSP标记(tag)，从而形成JSP文件(*.jsp)。

用JSP开发的Web应用是跨平台的，即能在Linux下运行，也能在其他操作系统上运行。

JSP技术使用Java编程语言编写类XML的tags和scriptlets，来封装产生动态网页的处理逻辑。网页还能通过tags和scriptlets访问存在于服务端的资源的应用逻辑。JSP将网页逻辑与网页设计和显示分离，支持可重用的基于组件的设计，使基于Web的应用程序的开发变得迅速和容易。