1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <%@taglib uri="/itcast" prefix="itcast" %> 3 4 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 5 <html> 6 <head> 7 8 <title>My JSP ‘1.jsp‘ starting page</title> 9 10 </head> 11 12 <body> 13 您的IP是： 14 <itcast:viewIP/> 15 </body> 16 </html>
JSP
1 package cn.itcast.web.tag;
2
3 import java.io.IOException;
4
5 import javax.servlet.http.HttpServletRequest;
6 import javax.servlet.jsp.JspException;
7 import javax.servlet.jsp.JspWriter;
8 import javax.servlet.jsp.tagext.TagSupport;
9
10
11 public class ViewIPTag extends TagSupport {
12
13 public int doStartTag() throws JspException{
14
15 HttpServletRequest request = (HttpServletRequest) this.pageContext.getRequest();
16 JspWriter out = this.pageContext.getOut();
17
18 String ip = request.getRemoteAddr();
19 try {
20 out.print(ip);
21 } catch (IOException e) {
22 throw new RuntimeException();
23 }
24
25 return super.doStartTag();
26 }
27
28
29
30
31
32 }
ViewIPTag
1 <?xml version="1.0" encoding="UTF-8" ?> 2 3 4 <taglib xmlns="http://java.sun.com/xml/ns/j2ee" 5 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 6 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" 7 version="2.0"> 8 <description>A tag library exercising SimpleTag handlers.</description> 9 <tlib-version>1.0</tlib-version> 10 <short-name>itcast</short-name> 11 <uri>/itcast</uri> 12 13 <tag> 14 <name>viewIP</name> 15 <tag-class>cn.itcast.web.tag.ViewIPTag</tag-class> 16 <body-content>empty</body-content> 17 </tag> 18 19 20 </taglib>
itcast.tld
1、编写一个实现tag接口的Java类
2、在tlb文件中对标签处理器类进行描述（tlb文件位置：WEB-INF下，可以抄）
3、在JSP页面中导入和使用自定义标签
标签简介和开发第一个标签
时间： 2024-11-10 14:57:04