JSTL Custom Function

/WEB-INF/tlds/customFunction.tld

<?xml version="1.0" encoding="UTF-8" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    version="2.0">

    <description>JSTL 1.1 functions library</description>
    <display-name>JSTL XML</display-name>
    <tlib-version>1.1</tlib-version>
    <short-name>cfn</short-name>

    <!-- 날짜의 DAY_OF_WEEK 를 가져온다. -->
    <function>
        <description>get Day of week</description>
        <name>dayOfWeek</name>
        <function-class>DateUtils</function-class>
        <function-signature>java.lang.Integer getDayOfWeek(java.util.Date)</function-signature>
        <example>
            ${cfn:dayOfWeek(date)}
       </example>
    </function>

</taglib>

DateUtils.java

public class DateUtils {

.....

    public static int getWeekOfYear(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);

        return cal.get(Calendar.WEEK_OF_YEAR);
    }

....

}

JSP

........

<%@ taglib prefix="cfn" uri="/WEB-INF/tlds/customFunction.tld" %>

<c:set var="date" value="<%=new java.util.Date()%>"/>

.......

${cfn:dayOfWeek(date) }