结构：
BinaryConverts.java
package com.jsp.tag;public class BinaryConverts { ???public static void main(String[] args) { ???????????????System.out.println(toBinaryString("10","10".length())); ???} ???????/** ????* 10进制转成2进制 ????* @param s ????* @param len ????* @return ????*/ ???public static String toBinaryString(String s,Integer len) { ???????try { ???????????String string = Integer.toBinaryString(Integer.valueOf(s)); ???????????int l = len - string.length(); ???????????for(int i=0;i<l;i++){ ???????????????string = "0"+string; ???????????} ???????????return string; ???????} catch (Exception e) { ???????????e.printStackTrace(); ???????} ???????return null; ???}}testFunction.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/j2eeweb-jsptaglibrary_2_0.xsd" ???????version="2.0"> ?????<tlib-version>1.0</tlib-version> ?????<short-name>mytest</short-name> ?????<uri>http://zhengcj.test.com</uri> ?????????<function> ?????????<!--EL页面调用名字--> ???????<name>toBinaryString</name> ?????????<!--指定标签的处理类，指定了标签由哪个Java类来处理。--> ???????<function-class>com.jsp.tag.BinaryConverts</function-class> ?????????<!--指定EL页面调用名字中实际调用的方法.指定处理类的实际方法.参数和回调函数要写完整路径--> ???????<function-signature> ?????????????java.lang.String toBinaryString(java.lang.String,java.lang.Integer) ?????????</function-signature> ?????</function> ????</taglib>
index.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" ???pageEncoding="UTF-8"%><%@taglib prefix="myFn" uri="/WEB-INF/tld/testFunction.tld"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body>${myFn:toBinaryString(‘10‘,4)}</body></html>访问：http://localhost:8090/JspTag/index.jsp
JSP自定义标签
原文地址：https://www.cnblogs.com/zcjyzh/p/9476264.html