JSP Tutorial: Expression Languages, Taglibs, and the Inclusion Directive

In this JSP tutorial, we’ll learn about Expression Languages, Taglibs, and Scriptlet. We’ll also cover the Inclusion directive. These are all very useful in a JSP project. You’ll be able to use them to create your custom tags and embed them on your page.

Taglibs

If you’re planning on using Taglibs in your Web application, you’ve come to the right place. This tutorial will give you an overview of the JSTL framework, including some of its features. Of course, the core tags must have a taglib prefix to work.

First, you’ll need to add a taglib directive to your JSP page. This directive specifies the tag library URI and the tag name prefix. Typically, this name is arbitrary, but try to keep it as short and straightforward as possible. The tag name can include body text, or it can have nested tags.

Scripting elements can use the myobj object by setting its id attribute to translation time. Another way to use the object is the tag developer’s tag-extra-info class to specify the type to instantiate for the thing. Then, you can pass the myobj object to the tag handler instance for foo and bar.

Expression Languages

The JSP Expression Language (EL) is a scripting language used to evaluate dynamic expressions within JSP pages. It is a simple, non-procedural scripting language. EL expressions can be placed in template text or passed as a value to a JSP action. Its simplicity makes it ideal for adding dynamic elements to a text output or HTML page.

The JSP Expression Language supports all Java operators. The highest precedence operators appear at the top of the expression table, while the lowest is at the bottom. Higher-precedence operators evaluate expressions first. In addition, if a term refers to an object, the object is considered.

Scriptlet

Scriptlet is an extension of the JSP language, which lets you write Java code within a JSP page. Scriptlet tags have the same access to automatically defined variables as expressions and must end with a semicolon (;). Scriptlet is a convenient way to create dynamic content within a JSP page. It is also used to implement the _jspService() functionality.

The Scriptlet class supports several methods. Among them is getServletContext(). This method returns an object containing the configuration of the current page.

Inclusion directives

An inclusion directive is a simple code that tells a servlet container to include an external file into a JSP page. In general, the enclosed order should be placed at the point in a document where a file is referenced. This is a helpful feature because you can reuse navigation bars, tables, and other objects without the need to recreate them. An included file may contain JSP, HTML, or other files. Having directives are also helpful in defining custom tags in your JSP pages.

An inclusion directive helps include content from any resource accessible to the JSP page. This resource can be a JSP file, an HTML file, or a text file. In both cases, the original content of the included file is included on the JSP page. An include directive in JSP is also known as a taglib directive. A standard tag library uses taglib directions to import data into JSP pages.

JavaBeans

You can use JavaBeans in a web application in a few ways. These components are very lightweight and can be created with just a few lines of code. JavaBeans also allow you to reuse the same parts in multiple applications. For example, you can reuse the bean that stores the URL of a web page. However, there are some disadvantages to using JavaBeans. They are not immutable, so you can’t take advantage of your application’s mutator and accessor properties.

The JSP language defines eight standard actions and five sub-actions. For example, the bold action appends the generated HTML code to the current page. This action differs from the include directive, which inserts unprocessed content into a page.