<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib prefix="t" uri="/WEB-INF/tag.tld"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
</head>
<body>
<%
request.setAttribute("user", "user");
%>
<t:if test="${user==null }">还没有登录</t:if>
<t:if test="${user!=null }">欢迎您： ${user }</t:if>
</body>
</html>
<?xml version="1.0" encoding="UTF-8" ?>
<!-- 文件名 /WEB-INF/referer.tld -->
<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">
<tlib-version>1.0</tlib-version>
<short-name>anyName</short-name><!-- 这个值可以任意设置 -->
<uri>anyUri</uri><!-- 这个Uri可以任意设置，但是不要与别的 .tld 文件相同 -->
<tag>
<name>if</name>
<tag-class>de.bvb.web.tag.IfTag</tag-class>
<body-content>scriptless</body-content>
<attribute>
<name>test</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
</tag>
</taglib>
package de.bvb.web.tag;
import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
public class IfTag extends SimpleTagSupport {
private boolean test;
public void setTest(boolean test) {
this.test = test;
}
@Override
public void doTag() throws JspException, IOException {
if (test) {
this.getJspBody().invoke(null); // 执行标签体
}
}
}
