struts2 的 append(追加)标签被用来组合几个迭代器(以列表或映射创建)成一个单一的迭代器。这里创建一个web工程：struts2appendtag，来演示在多个复选框如何设置的默认值，整个项目的结构如下图所示：
在本教程中，将使用struts2 <s:append>标签执行以下任务：
appendtagaction
package com.h3.common.action;
import java.util.arraylist;
import java.util.hashmap;
import java.util.list;
import java.util.map;
import com.opensymphony.xwork2.actionsupport;
public class appendtagaction extends actionsupport{
private list<string> list1 = new arraylist<string>();
private list<string> list2 = new arraylist<string>();
private list<string> list3 = new arraylist<string>();
private map<string,string> map1 = new hashmap<string,string>();
private map<string,string> map2 = new hashmap<string,string>();
private map<string,string> map3 = new hashmap<string,string>();
public string execute() {
list1.add("list1 - 1");
list1.add("list1 - 2");
list1.add("list1 - 3");
list2.add("list2 - 1");
list2.add("list2 - 2");
list2.add("list2 - 3");
list3.add("list3 - 1");
list3.add("list3 - 2");
list3.add("list3 - 3");
map1.put("map1-key1", "map1-value1");
map1.put("map1-key2", "map1-value2");
map1.put("map1-key3", "map1-value3");
map2.put("map2-key1", "map2-value1");
map2.put("map2-key2", "map2-value2");
map2.put("map2-key3", "map2-value3");
map3.put("map3-key1", "map3-value1");
map3.put("map3-key2", "map3-value2");
map3.put("map3-key3", "map3-value3");
return success;
}
//getter methods...
}
appenditerator.jsp
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head><title>struts2 append 标签示例 - by www.h3.com</title>
</head>
<body>
<h1>struts2 append 标签示例</h1>
1. combine 3 arraylist into a single iterator.
<s:append var="customlistiterator">
<s:param value="%{list1}" />
<s:param value="%{list2}" />
<s:param value="%{list3}" />
</s:append>
<ol>
<s:iterator value="%{#customlistiterator}">
<li><s:property /></li>
</s:iterator>
</ol>
2. combine 3 hashmap into a single iterator.
<s:append var="custommapiterator">
<s:param value="%{map1}" />
<s:param value="%{map2}" />
<s:param value="%{map3}" />
</s:append>
<ol>
<s:iterator value="%{#custommapiterator}">
<li><s:property /></li>
</s:iterator>
</ol>
3. combine arraylist and hashmap into a single iterator.
<s:append var="custommixediterator">
<s:param value="%{list1}" />
<s:param value="%{map1}" />
</s:append>
<ol>
<s:iterator value="%{#custommixediterator}">
<li><s:property /></li>
</s:iterator>
</ol>
</body>
</html>
<?xml version="1.0" encoding="utf-8" ?> <!doctype struts public "-//apache software foundation//dtd struts configuration 2.0//en" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.devmode" value="true" /> <package name="default" namespace="/" extends="struts-default"> <action name="appendtagaction" class="com.h3.common.action.appendtagaction" > <result name="success">/pages/appenditerator.jsp</result> </action> </package> </struts>
http://localhost:8080/struts2appendtag/appendtagaction.action
在浏览器中打开，显示结果如下：
struts 2 append tag example 1. combine 3 arraylist into a single iterator. 1. list1 - 1 2. list1 - 2 3. list1 - 3 4. list2 - 1 5. list2 - 2 6. list2 - 3 7. list3 - 1 8. list3 - 2 9. list3 - 3 2. combine 3 hashmap into a single iterator. 1. map1-key3=map1-value3 2. map1-key1=map1-value1 3. map1-key2=map1-value2 4. map2-key2=map2-value2 5. map2-key3=map2-value3 6. map2-key1=map2-value1 7. map3-key3=map3-value3 8. map3-key1=map3-value1 9. map3-key2=map3-value2 3. combine arraylist and hashmap into a single iterator. 1. list1 - 1 2. list1 - 2 3. list1 - 3 4. map1-key3=map1-value3 5. map1-key1=map1-value1 6. map1-key2=map1-value2
