<%@ taglib prefix="my" uri="http://jakarta.apache.org/tomcat/jsp2-example-taglib"%> <html> <head> <title>JSP 2.0 Expression Language - Functions</title> </head> <body> <h1>JSP 2.0 Expression Language - Functions</h1> <hr> An upgrade from the JSTL expression language, the JSP 2.0 EL also allows for simple function invocation. Functions are defined by tag libraries and are implemented by a Java programmer as static methods. <blockquote> <u><b>Change Parameter</b></u> <form action="functions.jsp" method="GET"> foo = <input type="text" name="foo" value="${param['foo']}"> <input type="submit"> </form> <br> <code> <table border="1"> <thead> <td><b>EL Expression</b></td> <td><b>Result</b></td> </thead> <tr> <td>\${param["foo"]}</td> <td>${param["foo"]} </td> </tr> <tr> <td>\${my:reverse(param["foo"])}</td> <td>${my:reverse(param["foo"])} </td> </tr> <tr> <td>\${my:reverse(my:reverse(param["foo"]))}</td> <td>${my:reverse(my:reverse(param["foo"]))} </td> </tr> <tr> <td>\${my:countVowels(param["foo"])}</td> <td>${my:countVowels(param["foo"])} </td> </tr> </table> </code> </blockquote> </body> </html>