Use of <fn:indexOf(String, String)> Tag of JSTL

In this section we will learn how to use <fn:indexOf> Tag of JSTL. This tag returns index of first occurrence of specified sub string in the given string string. This takes string type as arguments and returns int type.

Syntax :

int indexOf(java.lang.String,
      java.lang.String)

indexOf_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:indexof tag of JSTL</title>
    </head>
    <body>
        <form method="POST">
            This will calculate the first occurance of given 
            character/string in the <br>specified String.
            <table>
                <tr>
                    <td>Enter Text</td>
                    <td><input type="text" name="text"></td>
                </tr>

                <tr>
                    <td>Search</td>
                    <td><input type="text" name="str"></td>
                </tr>

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

            <font size="5" color="#1B2A0A">
                Index of first occurance : 
            </font>
            <font size="5" color="green">

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

This jsp code shows the following output :

Suppose in 'mahendra singh' string user want to find index of the first occurrence of 'e'....

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

Download Source Code

Use of Tag of JSTL

Use of Tag of JSTL

Use of <fn:indexOf(String, String)> Tag of JSTL

Tutorials