jstl ex

src\tld(package)\Gugudan.java 파일 생성
package tld;

public class Gugudan {
 public static String getGugu(String dan){
  String gugu = ""; 
  int d = Integer.parseInt(dan); 
  for(int i=1;i<=9;i++){
   gugu += d + "x" + i + "=" + d*i + "<br>";
  }
  return gugu;
 }
}

WEB-INF\tlds\tld-func.tld 파일 생성 (jsp - java파일을 연결시켜주는 역할)

<?xml version="1.0" encoding="euc-kr" ?>
<taglib version="2.0">
 
 <tlib-version>1.0</tlib-version>
 
 <function>
  <description>구구단 출력</description>
  <name>g</name>
  <function-class>
   tld.Gugudan
  </function-class>
  <function-signature>
   java.lang.String getGugu(java.lang.String)
  </function-signature>
 </function>
 
</taglib>


-----------------------------j s p-------------------------------

<%@ page contentType="text/html; charset=EUC-KR" %>
<%@ page session="true" %>
<%@ taglib prefix="elfunc" uri="/WEB-INF/tlds/tld-func.tld" %>

${elfunc:g(param.dan)}

-----------------------------j s p-------------------------------

<%@ page contentType="text/html; charset=EUC-KR" %>
<%@ page session="true" %>
<%@ taglib prefix="elfunc" uri="/WEB-INF/tlds/tld-func.tld" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<c:if test="${empty param.dan}">
 숫자를 입력하세요.
</c:if>

<c:if test="${!empty param.dan}">
 ${elfunc:g(param.dan)} 
</c:if>

-----------------------------j s p-------------------------------

<%@ page contentType="text/html; charset=EUC-KR" %>
<%@ page session="true" %>
<%@ taglib prefix="elfunc" uri="/WEB-INF/tlds/tld-func.tld" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<c:choose>
 <c:when test="${empty param.dan}">
  숫자를 입력하세요.
 </c:when>

 <c:when test="${!empty param.dan}">
  ${elfunc:g(param.dan)} 
 </c:when>

 <c:otherwise>음...</c:otherwise>
</c:choose>