Use of <fn:length(String)> Tag of JSTL

In this section we will learn how to use <fn:length> Tag of JSTL. This tag returns the number of items in a collection, or the number of characters in a string. This takes Object type as arguments and returns int type.

Syntax :

int length(java.lang.Object)

length_fnJstlTag.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>

<html>
    <head>
        <title>Example of fn:length tag of JSTL</title>
    </head>
    <body>
        <form method="POST">
            This will calculate the length of specified string.
            <table>
                <tr>
                    <td>Enter String</td>
                    <td><input type="text" name="text"></td>
                </tr>

                <tr>
                    <td></td>
                    <td><input type="submit" value="calculate"></td>
                </tr>
            </table>  
        </form>
        <c:if test="${pageContext.request.method=='POST'}">
            <c:set var="text" value="${param.text}"/>

            <font size="5" color="#1B2A0A">
                Length : 
            </font>
            <font size="5" color="green">

                <c:out value="${fn:length(text)}"/>
                
            </font>
        </c:if>
    </body>
</html>

This jsp code shows the following output :

Suppose in user wants to calculate the length of string 'mahendra singh'.....

When user clicks on calculate button, output will be.....

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Use of Tag of JSTL

Use of Tag of JSTL

Use of <fn:length(String)> Tag of JSTL

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