jsp自定义标签

来源：互联网发布：夏茗悠扒皮知乎编辑：程序博客网时间：2024/06/05 10:16

一：编写类

package cn.web.tag;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

@SuppressWarnings("serial")
public class ViewIpTag extends TagSupport{

public int doEndTag() throws JspException{

JspWriter out=this.pageContext.getOut();
HttpServletRequest request=(HttpServletRequest) this.pageContext.getRequest();

String ip=request.getLocalAddr();
try {
out.print(ip);
} catch (IOException e) {
throw new RuntimeException(e);
}
return super.doStartTag();
}

}

二：文件(注意：此文件应该放在WEB-INF目录下)

三：编写jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="http://www.clyao.cn" prefix="clyao" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'tag.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

</head>

<body>
您德 ip是：<clyao:viewIP/>
</body>
</html>

四：到此，恭喜您已经配好一个自定义标签。。。。