一.JSTL是：
apache开发的一套jsp标签，后来捐献给了sun，sun将其命名为jstl
二.JSTL的使用(ideal中)
1.导入jar包到pom文件中:
<!--jstl的jar-->
<dependency>
?<groupId>javax.servlet</groupId>
?<artifactId>jstl</artifactId>
?<version>1.2</version>
?<scope>runtime</scope>
</dependency>
2.jsp页面中使用taglib指令来导入jstl标签库中的标签
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
3.常见标签：
if标签： <c:if test=""></c:if>
forEach标签：<c:forEach var="" items=""></c:forEach>
choose标签：<c:choose></c:choose>
三：自定义jstl标签
步骤：
1，准备好Java方法，继承BodyTagSupport类
package cn.com.util;import java.util.List;import javax.servlet.http.HttpServletRequest;import javax.servlet.jsp.tagext.BodyTagSupport;import cn.com.dao.IPrivilegeDAO;import cn.com.entity.Privilege;import cn.com.entity.UserInfo;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.context.support.WebApplicationContextUtils;//标签public class AuthorizeTag ?extends BodyTagSupport { ???//你提供一个用户名字，我给一个用户拥有的权限集合，并且操作是在权限的DAO中 ???????private IPrivilegeDAO privilegeDAO; ???????private String URL; ???????public String getURL() { ?????????????return URL; ?????????} ???????????????????public void setURL(String uRL) { ?????????????URL = uRL; ?????????} ?????????@Override ?????????public int doStartTag() { ???????????// 如果URL不空就显示URL，否则就不显 ?????????????if (null != URL) { ???????????????getUserDao(); ???????????????HttpServletRequest request = (HttpServletRequest)pageContext.getRequest(); ???????????????UserInfo info=(UserInfo)request.getSession().getAttribute("userinfo"); ???????????????List<Privilege> list = privilegeDAO.findPrivilegeIdByUsername(info.getUserid()); ???????????????System.out.println(list.size()); ???????????????????????????????for (Privilege item : list) { ???????????????????System.out.println(URL+"=========================="); ???????????????????if(item.getUrl().equals(URL)){ ?????????????????????????//正确渲染该标签 ?????????????????????????return EVAL_BODY_INCLUDE; ?????????????????????} ???????????????} ?????????????????????????} ?????????????return this.SKIP_BODY; ?????????} ???????public void getUserDao() { ?????????????WebApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(pageContext.getServletContext()); ???????????privilegeDAO=(IPrivilegeDAO)applicationContext.getBean("IPrivilegeDAO"); ???????}}2，创建一个tld文件，将准备的方法添加到tld文件中
<?xml version="1.0" encoding="UTF-8" ?> ?<taglib xmlns="http://java.sun.com/xml/ns/javaee" ?????xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ?????xsi:schemaLocation="http://java.sun.com/xml/ns/javaee ??????http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" ?????version="2.1"> ?????<description> ?????<![CDATA[security Tags]]> ?????</description> ?????<tlib-version>1.0</tlib-version> ?????<short-name>security</short-name> ?????<uri>http://www.springsecurity.org/jsp</uri> ???<tag> ?????????<description> ?????????<![CDATA[authorize Tag]]> ?????????</description> ?????????<name>authorize</name> ?????????<tag-class> ????????????cn.com.util.AuthorizeTag ???????</tag-class> ?????????<body-content>JSP</body-content> ?????????<attribute> ?????????????<name>URL</name> ?????????????<required>false</required> ?????????????<rtexprvalue>true</rtexprvalue> ?????????????<type>java.lang.String</type> ?????????</attribute> ?????</tag> ?</taglib> ?
3，然后就可以在jsp中调用了
然后你就能用了：
<Authorize:authorize URL="/role/addRole">
??<a href="/role/addRole">添加角色</a>
</Authorize:authorize>
菜鸟一只，请多多关照，谢谢各路大神。。。！！！
自定义JSTl标签-----满足自身需求（JSTL标签库无法满足需求时）
原文地址：https://www.cnblogs.com/ruiannan/p/7898357.html