在JSP中引入JSTL标签库

<!-- JSTL 函数 包含一系列标准函数，大部分是通用的字符串处理函数-->
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn"%>

<!-- JSTL 核心标签库 -->
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<!-- JSTL 格式化标签 用来格式化并输出文本、日期、时间、数字 -->
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%>

<!-- JSTL SQL标签库 提供了与关系型数据库进行交互的标签 -->
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>

<!-- JSTL XML标签库 提供了建立和操做XML文档的标签 -->
<%@ taglib uri="http://java.sun.com/jsp/jstl/xml" prefix="x" %>

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