/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package lee; import javax.servlet.jsp.tagext.*; import javax.servlet.jsp.*; import java.io.*; import java.sql.*; import java.util.*; /** * * @author Administrator */ public class IteratorTag extends SimpleTagSupport { // 标签属性，用于指定需要被迭代的集合 private String collection; // 标签属性，指定迭代集合元素，为集合元素指定的名称 private String item; // collection的setter和getter方法 public void setCollection(String collection) { this.collection = collection; } public String getCollection() { return this.collection; } // item的setter和getter方法 public void setItem(String item) { this.item = item; } public String getItem() { return this.item; } // 标签的处理方法，标签处理类只需要重写doTag()方法 public void doTag() throws JspException, IOException { // 从page scope中获取名为collection的集合 Collection itemList = (Collection) getJspContext(). getAttribute(collection); // 遍历集合 for (Object s : itemList) { // 将集合的元素设置到page范围内 getJspContext().setAttribute(item, s); // 输出标签体 getJspBody().invoke(null); } } }
<?xml version="1.0" encoding="UTF-8"?> <taglib version="2.1" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"> <tlib-version>1.0</tlib-version> <short-name>mytaglib</short-name> <uri>/WEB-INF/tlds/mytaglib</uri> <!-- A validator verifies that the tags are used correctly at JSP translation time. Validator entries look like this: <validator> <validator-class>com.mycompany.TagLibValidator</validator-class> <init-param> <param-name>parameter</param-name> <param-value>value</param-value> </init-param> </validator> --> <!-- A tag library can register Servlet Context event listeners in case it needs to react to such events. Listener entries look like this: <listener> <listener-class>com.mycompany.TagLibListener</listener-class> </listener> --> <!-- 定义第一个标签 --> <!-- 定义第一个标签 --> <tag> <!-- 定义标签名 --> <name>helloWorld</name> <!-- 定义标签处理类 --> <tag-class>lee.HelloWorldTag</tag-class> <!-- 定义标签体为空 --> <body-content>empty</body-content> </tag> <!-- 定义第二个标签 --> <tag> <!-- 定义标签名 --> <name>query</name> <!-- 定义标签处理类 --> <tag-class>lee.QueryTag</tag-class> <!-- 定义标签体为空 --> <body-content>empty</body-content> <!-- 配置标签属性:driver --> <attribute> <name>driver</name> <required>true</required> <fragment>true</fragment> </attribute> <!-- 配置标签属性:url --> <attribute> <name>url</name> <required>true</required> <fragment>true</fragment> </attribute> <!-- 配置标签属性:user --> <attribute> <name>user</name> <required>true</required> <fragment>true</fragment> </attribute> <!-- 配置标签属性:pass --> <attribute> <name>pass</name> <required>true</required> <fragment>true</fragment> </attribute> <!-- 配置标签属性:sql --> <attribute> <name>sql</name> <required>true</required> <fragment>true</fragment> </attribute> </tag> <!-- 定义第三个标签 --> <tag> <!-- 定义标签名 --> <name>iterator</name> <!-- 定义标签处理类 --> <tag-class>lee.IteratorTag</tag-class> <!-- 定义标签体不允许出现JSP脚本 --> <body-content>scriptless</body-content> <!-- 配置标签属性:collection --> <attribute> <name>collection</name> <required>true</required> <fragment>true</fragment> </attribute> <!-- 配置标签属性:item --> <attribute> <name>item</name> <required>true</required> <fragment>true</fragment> </attribute> </tag> <tag> <!-- 定义标签名 --> <name>fragment</name> <!-- 定义标签处理类 --> <tag-class>lee.FragmentTag</tag-class> <!-- 指定该标签不支持标签体 --> <body-content>empty</body-content> <!-- 定义标签属性：fragment --> <attribute> <name>fragment</name> <required>true</required> <fragment>true</fragment> </attribute> </tag> <!-- 定义接受动态属性的标签 --> <tag> <name>dynaAttr</name> <tag-class>lee.DynaAttributesTag</tag-class> <body-content>empty</body-content> <!-- 指定支持动态属性 --> <dynamic-attributes>true</dynamic-attributes> </tag> </taglib>
<%-- Document : iteratorTag Created on : 2020-5-4, 23:29:17 Author : Administrator --%> <%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %> <%@ page import="java.util.*"%> <%@ taglib uri= "/WEB-INF/tlds/mytaglib" prefix="mytag"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title> 带标签体的标签-迭代器标签 </title> </head> <body> <h2>带标签体的标签-迭代器标签</h2><hr/> <% //创建一个List对象 List<String> a = new ArrayList<String>(); a.add("疯狂Java"); a.add("www.crazyit.org"); a.add("www.fkit.org"); //将List对象放入page范围内 pageContext.setAttribute("a", a); %> <table border="1" bgcolor="#aaaadd" width="300"> <!-- 使用迭代器标签，对a集合进行迭代 --> <mytag:iterator collection="a" item="item"> <tr> <td>${pageScope.item}</td> <tr> </mytag:iterator> </table> </body> </html>
