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