java代码:
package org.lxh.taglib; import java.util.List; public class FunctionTag { public static String hello(String name) { return name; } public static Integer bbq(List list) { return list.size(); } }
方法必须静态,可以定义有返回值或者void类型的方法.
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 http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0"> <tlib-version>1.0</tlib-version> <short-name>my</short-name> <uri>http://lauedward.spaces.live.com</uri> <function> <!--EL页面调用名字--> <name>hello</name> <!--指定标签的处理类,指定了标签由哪个Java类来处理。--> <function-class>org.lxh.taglib.FunctionTag</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 hello(java.lang.String)</function-signature> </function> <function> <name>bbq</name> <function-class>org.lxh.taglib.FunctionTag</function-class> <function-signature>java.lang.Integer bbq(java.util.List)</function-signature> </function> </taglib>
注意:在<function-signature>需要写完整的类名,假如是String类型的话就必须写java.lang.String这样字,不支持泛型的定义如java.util.List<java.lang.String>eclipse会把<>当作xml的格式来判断的,所以就省略该泛型的定义.
jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="my" uri="/WEB-INF/tld/testFunction.tld"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <%@page import="java.util.*"%><html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <% List<String> list = new ArrayList<String>(); list.add("aa"); list.add("bb"); list.add("cc"); request.setAttribute("list", "helloword"); request.setAttribute("name", list); Map map = new HashMap(); map.put("1","a"); map.put("2","b"); map.put("3","c"); map.put("4","d"); %> <br> ${my:hello(list)} <br> ${my:bbq(name)} <br> </body> </html>
注意:调用方法的时候必须类型要传入相同类型的值,否则的话会报错,不过对于方法体是String的话,是可以传入list,set,map那些,因为传入后会直接调用list的.toString()方法直接当字符串输出.
来源:http://www.cnblogs.com/edwardlauxh/archive/2010/05/19/1918589.html