Introduction to JSP Standard Template Library (JSTL)Posted by Infocampus HR on December 29th, 2017 JSTL was introduced was to allow JSP programmers to program using tags rather than Java code. To show why this is preferable, a quick example is in order. We will examine a very simple JSP page that counts to ten. We will examine this page both as regular scriptlet-based JSP, and then as JSTL. Installing JSTLTo use JSTL, you must have a JSP 1.2 (or higher) container installed. One of the most commonly used JSP containers is the Apache Tomcat Web server. You can obtain a copy of Tomcat from http://jakarta.apache.org/tomcat/. Using Tomcat alone will allow you to use regular JSP scriptlet code. To use JSTL, you must install JSTL into Tomcat. JSTL can be obtained from the same source as Tomcat. The main URL for JSTL is http://java.sun.com/products/jsp/jstl/. To use JSTL, you must unzip the distribution files and install them into the correct locations within Tomcat. To properly install JSTL for use with Tomcat, follow these three steps:
The JSTL Tag LibrariesJSTL is often spoken of as a single-tag library. JSTL is actually four tag libraries. These tag libraries are summarized as follows.
In this article, we will only take a brief look at a few of the core tags. We will examine a simple example that shows how to process data that a user enters into a form. Before we examine this program, we must first see how JSTL handles expressions. Expression handling in JSTL is accomplished by using the EL expression language, just as it is done in JSP 2.0. In the next section, we will examine the EL expression language. ConclusionsThis article showed you some of the differences between the JSTL and standard JSP scriptlet programming. As you can see, JSTL allows a more consistent programming environment by allowing both HTML and procedural code to be expressed as tags. JSTL and tag libraries represent a new method of programming Web pages. JSTL does not provide everything that a programmer would need to create a full-featured Web application. Further, some procedures that could be programmed in JSTL is often best not programmed in JSTL. One perfect example of this is the database JSTL tags. Except for very small Web applications, it is generally considered bad programming practice to embed actual database commands into a JSP page. The proper location for such program code is in Java beans and EJBs that will be used by your Web application. For such routines, you may consider creating your own tag libraries. This way, your JSP pages can use JSTL to perform basic programming procedures that are not unique to your business. You should implement your own tag libraries to implement components, which are unique to your business, which will be used by your Web application. JSTL allows you to create a very consistent programming JSP-based application. This is done not just through JSTL, but through a combination of JSTL, your own custom tag libraries, and an underlying database. Understanding each of these components allows you to deploy an effective Web application. Like it? Share it!More by this author |