jstl包及引用声明
各JSTL相关引用标记

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


<taglib> 
    <taglib-uri>http://java.sun.com/jsp/jstl/fmt</taglib-uri> 
    <taglib-location>/WEB-INF/tlds/fmt.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/fmt-rt</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/fmt-rt.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/core</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/c.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/core-rt</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/c-rt.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/sql</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/sql.tld</taglib-location>  </taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/sql-rt</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/sql-rt.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/x</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/x.tld</taglib-location> 
</taglib> 
          
<taglib> 
     <taglib-uri>http://java.sun.com/jsp/jstl/x-rt</taglib-uri> 
     <taglib-location>/WEB-INF/tlds/x-rt.tld</taglib-location> 
</taglib>