Shulou(Shulou.com)06/03 Report--

This article is to share with you about the characteristics of Java Servlet and the differences between JSP and JavaScript. The editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article. Let's take a look at it.

The Servlet program runs on the server side and generates Web pages dynamically. Compared with traditional CGI and many other CGI-like technologies, JavaServlet is more efficient, easier to use, more powerful, better portable, and more cost-effective.

What are the characteristics of JavaServlet

Efficient:

In traditional CGI, each request starts a new process. If the execution time of the CGI program itself is short, the cost of starting the process is likely to exceed the actual execution time. In Servlet, each request is handled by a lightweight Java thread (rather than a heavyweight operating system process).

In traditional CGI, if there are N concurrent requests for the same CGI program, the code of the CGI program is repeatedly loaded in memory for N times, while for Servlet, the request is handled by N threads, requiring only one copy of Servlet class code. Servlet also has more choices than CGI in terms of performance optimization, such as buffering previous calculations, maintaining database connectivity, and so on.

Convenient:

Servlet provides a large number of utility routines, such as automatically parsing and decoding HTML form data, reading and setting HTTP headers, processing Cookie, tracking session state, and so on.

Powerful:

In Servlet, many tasks that are difficult to accomplish with traditional CGI programs can be easily accomplished. For example, Servlet can interact directly with a Web server, while a normal CGI program cannot. Servlet can also share data among programs, making it easy to implement functions such as database connection pooling.

Good portability:

Servlet is written in Java, and ServletAPI has a complete standard. Therefore, Servlet written for I-PlanetEnterpriseServer can be ported to Apache, MicrosoftIIS, or WebStar without any substantial changes. Almost all major servers support Servlet directly or through plug-ins.

Save investment:

Not only are there many cheap or even free Web servers available for personal or small-scale websites, but for existing servers, if they don't support Servlet, these features tend to be free (or require very little investment).

JSP and its characteristics

JavaServerPages (JSP) is a technology that implements the hybrid coding of ordinary static HTML and dynamic HTML. For a description of the basic concepts of JSP, see "introduction to JSP Technology".

Many pages generated by CGI programs are still mostly static HTML, and dynamic content appears in only a limited number of parts of the page. But most CGI technologies, including Servlet, and their variants, always generate the entire page through the program. JSP allows us to create these two parts separately. For example, here is a simple JSP page:

< HTML >

< HEAD > < TITLE > Welcome to the online store < / TITLE > < / HEAD >

< BODY >

< H1 > Welcome < / H1 >

< SMALL > Welcome

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