struts标签logic:iterate学习

最新推荐文章于 2025-08-08 14:40:19 发布

转载最新推荐文章于 2025-08-08 14:40:19 发布 · 1.6k 阅读

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本文详细介绍了Struts框架中的逻辑标记库<logic:iterate>的使用方法及示例，展示了如何通过该标记循环遍历不同类型的集合，并控制循环的起始位置和长度。

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在逻辑标记库中定义了<logic:iterate>标记，它能够根据特定集合中元素的数目对标记体的内容进行重复的检查。集合的类型可以是java.util.Iterator,java.util.Collection,java.util.Map或是一个数组，也可以用name属性定义一个bean,并且使用property属性指定要循环的bean的属性（这个属性返回集合）类型。

下面请看struts1.2.4中自带的例子：

<%@ taglib uri="/tags/struts-bean" prefix="bean" %>

<%@ taglib uri="/tags/struts-logic" prefix="logic" %>

<html>

<head>

<title>测试struts-logic Iterate 标记</title>

</head>

{

java.util.ArrayList list = new java.util.ArrayList();

list.add("First");

list.add("Second");

list.add("Third");

list.add("Fourth");

list.add("Fifth");

pageContext.setAttribute("list", list, PageContext.PAGE_SCOPE);

int intArray[] = new int[]

{ 0, 10, 20, 30, 40 };

pageContext.setAttribute("intArray", intArray, PageContext.PAGE_SCOPE);

}

<h1>测试struts-logic Iterate标记</h1>

</div>

<jsp:useBean id="bean" scope="page" class="org.apache.struts.webapp.exercise.TestBean" />

<jsp:useBean id="list" scope="page" class="java.util.ArrayList" />

<h3>测试1 - 从头到尾叠代（循环）一个字符串数组[0..4]</h3>

<ul>

<logic:iterate id="element" name="bean" property="stringArray" indexId="index1">

<li>

<em>

<bean:write name="element" />

</em> [

<bean:write name="index1" />]</li>

</logic:iterate>

</ul>

<h3>测试2 - 叠代一个字符串数组（循环三次）Array [0..2]</h3>

<ul>

<logic:iterate id="element" name="bean" property="stringArray" indexId="index" length="3">

<li>

<em>

<bean:write name="element" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试3 - 叠代一个String Array [3..4]（输出索引从3开始的元素）</h3>

<ul>

<logic:iterate id="element" name="bean" property="stringArray" indexId="index" offset="3">

<li>

<em>

<bean:write name="element" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试4 - 叠代一个String Array [1..3]</h3>

<ul>

<logic:iterate id="element" name="bean" property="stringArray" indexId="index" offset="1" length="3">

<li>

<em>

<bean:write name="element" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试5 - 从头至尾叠代一个Array List</h3>

<ul>

<logic:iterate id="item" name="list" indexId="index">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试6 - 叠代一个Array List [0..2]</h3>

<ol>

<logic:iterate id="item" name="list" indexId="index" offset="0" length="3">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ol>

<h3>测试7 - 叠代一个Array List [2..4]</h3>

<ol>

<logic:iterate id="item" name="list" indexId="index" offset="2" length="3">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ol>

<h3>测试8 - 叠代一个int array</h3>

<ul>

<logic:iterate id="item" name="intArray" indexId="index">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试 9 - 叠代一个int array [0..2]</h3>

<ul>

<logic:iterate id="item" name="intArray" indexId="index" length="3">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

<h3>测试10 - 叠代一个int array [2..4]</h3>

<ul>

<logic:iterate id="item" name="intArray" indexId="index" offset="2" length="3">

<li>

<em>

<bean:write name="item" />

</em> [

<bean:write name="index" />]</li>

</logic:iterate>

</ul>

</body>

</html>

下面是TestBean.java的部分：

package org.apache.struts.webapp.exercise;

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Vector;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts.action.ActionForm;

import org.apache.struts.action.ActionMapping;

import org.apache.struts.util.LabelValueBean;

public class TestBean extends ActionForm {

//省略......................................................

private String stringArray[] =

{ "String 0", "String 1", "String 2", "String 3", "String 4" };

public String[] getStringArray() {

return (this.stringArray);

}

public void setStringArray(String stringArray[]) {

this.stringArray = stringArray;

}

//省略........................................................

}