Елдос,

из http://www.tutorialspoint.com/jsp/jsp_standard_tag_library.htm

авторInstall JSTL Library:
If you are using Apache Tomcat container then follow the following two simple steps:

Download the binary distribution from Apache Standard Taglib and unpack the compressed file.

To use the Standard Taglib from its Jakarta Taglibs distribution, simply copy the JAR files in the distribution's 'lib' directory to your application's webapps\ROOT\WEB-INF\lib directory.

To use any of the libraries, you must include a <taglib> directive at the top of each JSP that uses the library.

вы это сделали?

какую ide используете?

Елдос,

http://tomcat.apache.org/taglibs/index.html