What is a JSP? What do you mean by JSP? _JSP programming

JSP (Java Server pages) is a Dynamic Web page technology standard that is initiated by Sun Microsystems Corporation and many companies are involved in. JSP technology is similar to the ASP technology, it is in the traditional Web page HTML file (*.htm,*.html) Insert Java program Segment (scriptlet) and JSP tags (tag), thus forming a JSP file (*.jsp). Web applications developed with JSP are Cross-platform, run on Linux, and run on other operating systems.

a simple introduction to JSP

JSP technology uses the Java programming language to write tags and scriptlets of class XML to encapsulate the processing logic of generating dynamic Web pages. Web pages can also access the application logic of resources that exist on the server via tags and scriptlets. The JSP separates the logic of the Web page from the display of the web design, supports reusable component-based design, and makes the development of web-based applications fast and easy. JSP (JavaServer pages) is a dynamic page technology whose primary purpose is to separate presentation logic from the servlet.

When a Web server encounters a request to access a JSP Web page, it first executes the program segments in it, and then returns the results of the execution along with the HTML code in the JSP file to the client. The inserted Java program segment can manipulate databases, redirect Web pages, and so on to achieve the functionality required to build dynamic Web pages.

JSP, like Javaservlet, is executed on the server side, and is usually returned to the client is an HTML text, so the client can browse as long as there is a browser.

The final version of the JSP's 1.0 specification was launched in September 1999, and the 1.1 specification was introduced in December. 　　 At present, the newer is the JSP1.2 standard, the JSP2.0 standard draft has also been issued. JSP pages are made up of HTML code and embedded Java code. The server processes the Java code after the page is requested by the client, and then returns the resulting HTML page to the client's browser. Java servlet is the technical basis of JSP, and the development of large Web applications requires Java servlet and JSP coordination to complete. JSP has the simplicity of Java technology, fully object-oriented, platform-independent and safe and reliable, mainly for all the features of the Internet.

Since the introduction of JSP, many large companies support JSP technology servers, such as IBM, Oracle, BEA, etc., so JSP quickly become a commercial application of the server-side language.

The JSP can be expressed as a simple and understandable equation: html+java+jsp tag =jsp.

the strength of JSP technology


(1) Write once and run everywhere. In addition to the system, the code does not have to make any changes.
(2) Multi-platform support of the system. Can be developed in virtually any environment on all platforms, system deployment in any environment, and extended in any environment. The advantages of ASP.net are obvious compared to the limitations of the JSP.
(3) Strong scalability. From only a small jar file can run servlet/jsp, to be clustered and load-balanced by multiple servers, to multiple application for transaction processing, message processing, a server to countless servers, Java shows a huge vitality.
(4) Diverse and powerful development tool support. This is similar to the ASP, Java has a lot of very good development tools, and many can be free, and many of them have been able to run smoothly under a variety of platforms.
(5) Support server-side components. Web applications require powerful server-side components to support, and developers need to use other tools to design components that implement complex functionality for Web page calls to enhance system performance. JSP can use a mature Java BEANS component to implement complex business functions.
the weakness of JSP technology

(1) Like the ASP, some of Java's advantages are its fatal problems. It is precisely because of the cross-platform capabilities, in order to extreme scalability, so greatly increased the complexity of the product.
(2) Java is running at the speed of the class resident memory to complete, so it in some cases the memory used than the number of users is indeed the "lowest performance price ratio." On the other hand, it requires hard disk space to store a series of. Java and. class files, as well as the corresponding version files.