自定义标签简单实例---入门
结构如下：
①创建page.tld文件：
<?xml version="1.0" encoding="utf-8" ?><!DOCTYPE taglibPUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN""http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"><taglib><!--定义标签版本库 --><tlib-version>1.0</tlib-version><!--定义jsp版本库 --><jsp-version>1.2</jsp-version><short-name>Cms Tag</short-name><uri>http://www.gdie.page</uri><description><!--标签描述- -->A simple appbase tag library</description><tag><name>page</name><!--tag的名字 --><tag-class>com.cms.common.tag.PageTag</tag-class><!--tag对应的java类的名字 --><body-content>empty</body-content><!--关于body-content 有三个值可选;empty：标签体必须为空;jsp：标签由其他jsp元素组成比如标签中含有<%=attributeName%>的jsp元素,那么此时body-content的值就是实际attributeName传入的值;tagdependent:有标签解释不带jsp转换（这个深入的含义不太了解） --><attribute><!---这里表示的是这个tag的一个参数 --><name>cmsform</name><!--这个参数的名字 --><required>true</required><!--是否是必填选项 --><rtexprvalue>true</rtexprvalue><!--这个参数的值是否可以写入，换句话说 就是这个参数是否可以动态赋值 --></attribute></tag></taglib>
②PageTag.java
package com.cms.common.tag;import javax.servlet.jsp.JspException;import javax.servlet.jsp.JspWriter;import javax.servlet.jsp.tagext.TagSupport;public class PageTag extends TagSupport {private static final long serialVersionUID = 1L;private String cmsform = "";public String getCmsform() {return cmsform;}public void setCmsform(String cmsform) {this.cmsform = cmsform;}public int doStartTag(){return super.SKIP_BODY;}public int doEndTag() throws JspException{JspWriter writer=pageContext.getOut();try {writer.print("这是我的标签示例<br/>"+"cmsform :"+this.cmsform);} catch (Exception e) {e.printStackTrace();}return super.EVAL_PAGE;}}
③web.xml
<?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_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>springmvc3</display-name> <jsp-config><taglib><taglib-uri>http://www.gdie.page</taglib-uri><taglib-location>/tld/page.tld</taglib-location></taglib> </jsp-config> <welcome-file-list> <welcome-file>/index.jsp</welcome-file> </welcome-file-list></web-app>
④index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="jason" uri="http://www.gdie.page" %><!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><jason:page cmsform="success..."/></body></html>
运行效果如下：
