jsp技术网站设计外文翻译.doc

Combining JSP and Servlets

The technology of JSP and Servlet is the most important technology which use Java

technology to exploit request of server, and it is also the standard which exploit business

application .Java developers prefer to use it for a variety of reasons, one of which is

already familiar with the Java language for the development of this technology are easy to

learn Java to the other is "a preparation, run everywhere" to bring the concept of Web

applications, To achieve a "one-prepared everywhere realized." And more importantly, if

followed some of the principles of good design, it can be said of separating and content to

create high-quality, reusable, easy to maintain and modify the application. For example, if

Early dynamic pages mainly CGI (Common Gateway Interface, public Gateway

Interface) technology, you can use different languages of the CGI programs, such as VB, C

/ C + + or Delphi, and so on. Though the technology of CGI is developed and powerful,

because of difficulties in programming, and low efficiency, modify complex shortcomings,

it is gradually being replaced by the trend. Of all the new technology, JSP / Servlet with

more efficient and easy to program, more powerful, more secure and has a good portability,

they have been many people believe that the future is the most dynamic site of the future

development of technology.

Similar to CGI, Servlet support request / response model. When a customer submit a

request to the server, the server presented the request Servlet, Servlet responsible for

treatment (DoGet / doPost / doHead…) and generate a response.

Although such a complex, in fact, simply said to Servlet is a Java class. And the

general category of the difference is that this type operating in a Servlet container, which

can provide session management and targeted life-cycle management. So that when you

use the Servlet, you can get all the benefits of the Java platform, including the safety of the

management, use JDBC access the database and cross-platform capability. Moreover,

Servlet using thread, and can develop more efficient Web applications.

JSP technology is a key J2EE technology, it at a higher level of abstraction of a

Servlet. It allows conventional static and dynamic HTML content generated by combining

an HTML page looks like, but as a Servlet to run. There are many commercial application

server support JSP technology, such as BEA WebLogic, IBM WebSphere, JRun, and so on.

JSP and Servlet use more than simple. If you have a JSP support for Web servers, and a

JSP document, you can put it Fangdao any static HTML files can be placed, do not have to

compile, do not have to pack, do not have to ClassPath settings, you can visit as ordinary

Web It did visit, the server will automatically help you to do other work.

Figure 1: Calling the process of JSP pages

After another visit this page to the customer, as long as the paper there have been no

changes, JSP engine has been loaded directly call the Servlet. If you have already been

modified, it will be once again the implementation of the above process, translate, compile

and load. In fact, this is the so-called "first person to punishment." Because when the first

visit to the implementation of a series of the above process, so will spend some time after

such a visit would not.

A servlet is a Java class that extends a server with functionality for processing a

request and producing a response. It's implemented using the classes and interfaces defined

by the Servlet API. The API consists of two packages: the javax.servlet package contains

classes and interfaces that are protocol-independent, while the javax.servlet.http package

provides HTTP-specific extensions and utility classes.

What makes a servlet a servlet is that the class implements an interface named

javax.servlet.Servlet, either directly or by extending one of the support classes. This

interface defines the methods used by the web container to manage and interact with the