JavaServer Pages, 3rd Edition

JSP Standard Tag Library

The third group is called JSP Standard Tag Library (JSTL) actions. Until very recently, programmers had to develop custom actions even for very generic tasks, such as selecting different parts of a page based on a runtime condition or looping through a collection of data; none of the JSP standard actions support these common tasks. The result was, of course, that every Java programmer with some self-respect implemented a set of custom actions for all the generic tasks her JSP team needed. To reduce this programming effort, and avoid the confusion caused by a zillion different implementations of if and loop actions with slightly different features, a group of experienced tag library developers (including yours truly) came together through the Java Community Process to define what’s called the JSP Standard Tag Library. Version 1.0 was released in June 2002 and Version 1.1, aligning JSTL with JSP 2.0, was released a year later. While the name of the standard contains the word “library” (singular), it’s in fact a set of libraries that group related actions:

Core

Conditional processing and looping, importing data from external sources, etc.

XML processing

Processing of XML data, such as transforming and accessing individual elements

Internationalization (I18N) and formatting

Format and parse localized information, insert localized information in a page

Relational database access (SQL)

Read and write relational database data

Functions

A set of generic Expression Language ...