自定义标签

最新推荐文章于 2025-10-12 23:30:58 发布

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#java #web.xml

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本文介绍如何在JSP中自定义标签和函数标签，包括定义处理类、配置tld文件及web.xml，最终在JSP页面中使用。

1. 自定义标签，输出到页面上（可用于css、scripte等标签简写）

首先：定义标签处理类

package com.inspur.test.taglabel;
import java.io.IOException;

import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

public class testTagLabel extends TagSupport {
	private String name = "lili";
	private String pwd = "lucky";
	public int  doStartTag (){
		try {
			JspWriter out = this.pageContext.getOut();
			out.println("===============lili+++lucky============");
			out.println("<br>");
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return SKIP_BODY;
	}
}

其次，定义标签tld

<?xml version="1.0" encoding="UTF-8"?>
<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 web-jsptaglibrary_2_0.xsd"
	version="2.0">
	<tlib-version>1.0</tlib-version>
	<jsp-version>2.0</jsp-version>
	<short-name>jsplabel</short-name>
	<uri>/tags/tagtest</uri>
	<tag>
	    <name>showUserInfo</name>
	    <tag-class>com.inspur.test.taglabel.testTagLabel</tag-class>
	    <body-content>empty</body-content>
	    <attribute>
	        <name>user</name>
	         <required>false</required>
	         <rtexprvalue>true</rtexprvalue>
	         <type>java.lang.String</type>
	    </attribute>
	    <attribute>
			<name>pwd</name>
			<required>false</required>
			<rtexprvalue>true</rtexprvalue>
			<type>java.lang.String</type>
			</attribute>
	 </tag>
</taglib>

然后，在web-inf下的web.xml里配置映射

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>testJsp</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <jsp-config>
		<taglib>
			<taglib-uri>/tags/tagtest</taglib-uri>
			<taglib-location>/WEB-INF/tagtest.tld</taglib-location>
		</taglib>
	</jsp-config>
</web-app>

最后，在jsp里使用：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="jsplabel" uri="/tags/tagtest"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<jsplabel:showUserInfo/>
</body>
</html>

输出结果：

===============lili+++lucky============

如果是<script .........>====>可以被解析成引入js，简单方便

2. 自定义函数标签

首先：定义标签处理类，一定注意，定义的函数必须是public static的，切记

package com.inspur.test.taglabel;

public class TestFunLabel {
	public static String  getUserName (){
		return "=============name==lili========";
	}
}

其次，定义函数标签tld

<?xml version="1.0" encoding="UTF-8"?>
<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 web-jsptaglibrary_2_0.xsd"
	version="2.0">
	<tlib-version>1.0</tlib-version>
	<jsp-version>2.0</jsp-version>
	<short-name>jsplabel</short-name>
	<uri>/tags/testfun</uri>
	<function>
		<name>getUserName</name>
		<function-class>com.inspur.test.taglabel.TestFunLabel</function-class>
		<function-signature>java.lang.String  getUserName()</function-signature>   
    </function>
</taglib>

然后，在web-inf下的web.xml里配置映射

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">
	<display-name>testJsp</display-name>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
		<welcome-file>index.htm</welcome-file>
		<welcome-file>index.jsp</welcome-file>
		<welcome-file>default.html</welcome-file>
		<welcome-file>default.htm</welcome-file>
		<welcome-file>default.jsp</welcome-file>
	</welcome-file-list>
	<jsp-config>
		<taglib>
			<taglib-uri>/tags/testfun</taglib-uri>
			<taglib-location>/WEB-INF/tlds/funtest.tld</taglib-location>
		</taglib>
	</jsp-config>
	
</web-app>

最后，在jsp里使用：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="fn" uri="/tags/testfun"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
${fn:getUserName()}
</body>
</html>

输出结果：‘

=============name==lili========