JSP 2.0 is released with new promises. JSP 2.0 is a
upgrade version of JSP 1.2 with several new and interesting features. This
version is fully compatible with JSP1.2. These features have been added to make
the life of web application developers and designers easier. The main objective
of the JSP 2.0 is to make JSP easier than ever, it has been made in such a way
that it can be learn without the knowledge of Java. After going through this
tutorial you will be better understand the features added in JSP 2.0.
The Features in JSP 2.0 are:
Simple Expression Language(EL): Expression Language
(EL), provides a way to simplify expressions in JSP. EL provides the ability
to use run-time expressions outside JSP scripting elements. Scripting
elements are those elements which is used to embed Java code inside the JSP
file. Mostly it contains the logic of the program. Scripting elements have
Declaration: The variables and methods are declared inside
Scriptlets: The business logic of the program is written
Expressions: output will be displayed by the
Expression Language can be enabled in scriptfree JSP pages:
1). By using a page directive: We can enable EL by using
JSP Fragments: Jsp fragments is a new feature
of JSP 2.0 which allows page author to create custom action fragments that
can be invoked. The JSP fragments allows a portion of Jsp code to be
encapsulated into a Java object that can be passed around and evaluated zero
or more times. Methods for creating a JSP fragment:
1). Providing the body of a <jsp:attribute>:
Easy tags creation with .tag files: With the
introduction of JSP 2.0, knowledge of Java is no longer a prerequisite to
create a custom tag action.
Easy Header and Footer template using the prelude
and coda includes
With JSP 2.0 web development has become easy and
it also helps in maintaining dynamic web pages easily. To learn JSP 2.0 there is
no need to learn java.
Features of jsp2.1
The main purpose of Java Platform, Enterprise
Edition (Java EE) 5 is to ease development. Now the Jsp2.1 includes the Java
Standard Tag Library(JSTL) and JavaServerFaces technology.
This version has new expression language (EL )
syntax that allows deferred evaluation of expressions. It now enables using
the expression to both get and set data and to invoke methods, and
facilitates customizing the resolution of a variable or property referenced
by an expression.
It supports resource injection through annotations
to simplify configuring access to resources and environment data.
It has complete alignment of Jsf technology tags and
Jsp software code. Earlier the version 1.0 of jsf technology depended
on jsp 1.2 technology. The reason is that the Jsp 1.2 was already available
at the time, and the intension was to make the Jsf 1.0 interface more
accessible to a broader audience. As jsp1.2 does not have an integrated
expression language and because the Jsp 2.0 EL does not meet all of the
needs of Jsf, therefore jsp2.1 was developed to enhance the expression
language to meet the needs of Jsf technology.
Qualified functions now take precedence over the
ternary operator when the "." operator in use or we can say that
ability to redefine the behavior of the "."operator through a
Property Resolver API.
EL now supports "literal expressions". The
expression which were previously considered to be non-EL value text must now
be considered an EL expression.
EL now supports Java 5.0 enumerations.
Ability to plug in
Property Resolvers on a per-application and per-page basis.
Ability to express references to bean methods using
the expression language and invoking those methods via a Method Binding API.