package mypack;
import java.util.*;
public class Tool {
public static int add(String x, String y) {
int a = 0;
int b = 0;
try {
a = Integer.parseInt(x);
b = Integer.parseInt(y);
}catch(Exception e) {}
return a + b;
}
public static String convert(String s,String encode1,String encode2){
try{
return new String(s.getBytes(encode1),encode2);
}catch(Exception e){return null;}
}
}
<%@ page contentType="text/html; charset=GB2312" %>
<%@ taglib prefix="mm" uri="/mytaglib" %>
<html>
<head>
<title>functions</title>
</head>
<body>
<h3>Add Numbers</h3>
<p>
<form action="sum.jsp" method="get">
user= <input type="text" name="user"
value="${mm:convert(param.user,'ISO-8859-1','GB2312')}">
<br>
x = <input type="text" name="x" value="${param.x}">
<br>
y = <input type="text" name="y" value="${param.y}">
<input type="submit" value="Add Numbers">
</form>
<p>
the sum is: ${mm:add(param.x,param.y)}
</body>
</html>
mytaglib.tld
<?xml version="1.0" encoding="ISO-8859-1" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd"
version="2.0">
<tlib-version>1.1</tlib-version>
<short-name>mytaglib</short-name>
<uri>/mytaglib</uri>
<function>
<description>add x and y</description>
<name>add</name>
<function-class>mypack.Tool </function-class>
<function-signature>
int add(java.lang.String,java.lang.String)
</function-signature>
</function>
<function>
<description>convert encoding</description>
<name>convert</name>
<function-class>mypack.Tool </function-class>
<function-signature>
java.lang.String convert(java.lang.String,java.lang.String,java.lang.String)
</function-signature>
</function>
</taglib>
web.xml
<taglib>
<taglib-uri>/mytaglib</taglib-uri>
<taglib-location>/WEB-INF/mytaglib.tld</taglib-location>
</taglib>
从 <http://ndebyq.blog.51cto.com/274018/148005> 插入
源文档 <http://hi.baidu.com/cliff77/blog/item/2ccfaf381bd28721b9998fcb.html>
<%@ taglib prefix="my" uri="http://jakarta.apache.org/tomcat/jsp2-example-taglib"%>
<html>
<head>
<title>JSP 2.0 Expression Language - Functions</title>
</head>
<body>
<h1>JSP 2.0 Expression Language - Functions</h1>
<hr>
An upgrade from the JSTL expression language, the JSP 2.0 EL also
allows for simple function invocation. Functions are defined
by tag libraries and are implemented by a Java programmer as
static methods.
<blockquote>
<u><b>Change Parameter</b></u>
<form action="functions.jsp" method="GET">
foo = <input type="text" name="foo" >
<input type="submit">
</form>
<br>
<code>
<table border="1">
<thead>
<td><b>EL Expression</b></td>
<td><b>Result</b></td>
</thead>
<tr>
<td>\${param["foo"]}</td>
<td>${fn:escapeXml(param["foo"])} </td>
</tr>
<tr>
<td>\${my:reverse(param["foo"])}</td>
<td>${my:reverse(fn:escapeXml(param["foo"]))} </td>
</tr>
<tr>
<td>\${my:reverse(my:reverse(param["foo"]))}</td>
<td>${my:reverse(my:reverse(fn:escapeXml(param["foo"])))} </td>
</tr>
<tr>
<td>\${my:countVowels(param["foo"])}</td>
<td>${my:countVowels(fn:escapeXml(param["foo"]))} </td>
</tr>
</table>
</code>
</blockquote>
</body>
</html>
