SSH：Struts1框架（自定义标签函数库）_struts 1自定义tag-优快云博客

本文介绍了一个使用JSTL函数库及自定义函数库的示例项目，包括了JSP页面如何利用这些函数库进行数据处理与展示。通过具体的代码实现了字符串长度获取、列表大小获取及自定义问候消息等功能。

JSTL函数库

1.JstlFnAction.java

package com;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

public class JstlFnAction extends Action {

@Override
public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response)
   throws Exception {

  request.setAttribute("hello", "Hello World !");

  List<String> list = new ArrayList<String>();
  list.add("a");
  list.add("b");
  request.setAttribute("list", list);

  request.setAttribute("username", "KIMURA SAORI");
  return mapping.findForward("success");
}

}

2.jstl_fn.jsp

<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%@ taglib prefix="mf" uri="myURI" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030">
<title>测试JSTL函数库</title>
</head>
<body>
<h1>测试JSTL函数库</h1><hr>
<li>JSTL函数库</li><br>
hello.length(JSP脚本)=<%=request.getAttribute("hello").toString().length() %><br>
hello.length(JSTL标签)=${fn:length(hello) }<br>
list.size=${fn:length(list) }<br>
<p>
<li>测试自定义函数库</li><br>
sayHello:${mf:sayHello(username) }
</body>
</html>

注：使用自定义函数库

* 定义类和方法（方法必须是public static）

* 编写自定义tld文件，并且将此文件放到WEB-INF或WEB-INF任意子目录下

3.my.tld，放到WEB-INF下

<?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">

  <description>my functions library</description>
  <display-name>my functions</display-name>
  <tlib-version>1.1</tlib-version>
  <short-name>mf</short-name>
  <uri>myURI</uri>

  <function>
    <name>sayHello</name>
    <function-class>com.MyFunction</function-class>
    <function-signature>java.lang.String sayHello(java.lang.String)</function-signature>
  </function>