構造一個雙層列表：
outList = new ArrayList(); inList= new ArrayList();inList.add(new Element("1","a"));inList.add(new Element("2","b"));outList.add(inList); inList= new ArrayList();inList.add(new Element("3","c"));inList.add(new Element("4","d"));outList.add(inList);遍歷：<ww:iterator value="outList"> <ww:iterator value="top"> <ww: property value="key"/>,<ww: property value="value"/> </ww:iterator></ww:iterator>注意：關鍵點就一個top，意思是取棧頂的元素.
起因：使用webwork+spring開發，出現提交數據亂碼。
1，首先嘗試修改webwork配制文件webwork.properties
webwork.locale=zh_CN
webwork.i18n.encoding=UTF-8
沒有解決問題
2，再次嘗試加入filter
<filter>
<filter-name>SetCharacterEncoding</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>SetCharacterEncoding</filter-name>
<url-pattern>*.jsp</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>SetCharacterEncoding</filter-name>
<url-pattern>*.action</url-pattern>
</filter-mapping>
還是沒有解決問題。
3，嘗試更改提交方式 ,頁面上加上 method="post"
問題解決。但是新問題出現，url中出現的中文依然是亂碼
更改tomcat server.xml文件，在<Connector port="8080" >中加入URIEncoding="utf-8"問題解決，
但有更好的一種解決方案。就是用useBodyEncodingForURI="true"代替URIEncoding="utf-8"
這樣tomcat會根據頁面的編碼去處理
sitemesh應用Decorator模式，用filter截取request和response,把頁面組件head,content,banner
結合為一個完整的視圖。通常我們都是用include標簽在每個jsp頁面中來不斷的包含各種header,
stylesheet, scripts and footer，現在，在sitemesh的幫助下，我們可以開心的刪掉他們了
下邊是創建一個簡單實例的步驟：
1，新建一個標準的web工程叫sitemesh
在WebRoot下新建一個index.jsp,內容如下
<% @ page contentType = " text/html; charset=utf-8 " %> 2
this is index.jsp.3
it ' s a simple page 接著在webRoot下新建幾個目錄
style2
login
shared
在login下建立目錄style3
然後把index.jsp分別復制到style2，login/style3,shared下
現在訪問下邊的鏈接:
http://localhost:8080/sitemesh/index.jsp
http://localhost:8080/sitemesh/style2/index.jsp
http://localhost:8080/sitemesh/login/style3/index.jsp
http://localhost:8080/sitemesh/shared/index.jsp
得到的結果是一樣的，那我們如何讓這四個相同的index.jsp有不同的樣式呢。除了每個里邊加入include
還有個解決辦法，就是sitemesh
2,在opensymphony.sourceforge.net下載sitemesh.jar ,sitemesh-decorator.tld,sitemesh-page.tld
三個文件。
復制sitemesh.jar到WEB-INF/lib下，
復制sitemesh-decorator.tld,sitemesh-page.tld到WEB-INF下
把下邊這部分加入web.xml
------------------------------------------------------------------------------
<filter>
<filter-name>sitemesh</filter-name>
<filter-class>com.opensymphony.module.sitemesh.filter.PageFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>sitemesh</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<taglib>
<taglib-uri>sitemesh-decorator</taglib-uri>
<taglib-location>/WEB-INF/sitemesh-decorator.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>sitemesh-page</taglib-uri>
<taglib-location>/WEB-INF/sitemesh-page.tld</taglib-location>
</taglib>
--------------------------------------------------------------------------------
在WEB-INF下建立一個decorators.xml，內容如下
excludes代表不使用的部分
其它三個是匹配url，使用style
--------------------------------------------------------------------------
<decorators defaultdir="/decorators">
<excludes>
<pattern>/shared/*</pattern>
</excludes>
<decorator name="style1" page="style1.jsp">
<pattern>/*</pattern>
</decorator>
<decorator name="style2" page="style2.jsp">
<pattern>/style2/*</pattern>
</decorator>
<decorator name="style3" page="style3.jsp">
<pattern>/*/style3/*</pattern>
</decorator>
</decorators>
--------------------------------------------------------------------------
在WebRoot下新建一個目錄decorators
然後在下邊建立三個jsp文件,內容如下
------------------------------------------------------------------
<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib uri="sitemesh-decorator" prefix="decorator" %>
<html>
<head>
<title><decorator:title default="裝飾器頁面..." /></title>
<decorator:head />
</head>
<body>
<p><font color="red">this is style2's header</font></p>
<hr>
<decorator:body />
<hr>
<p><font color="red">this is style1's footer</font></p>
</body>
</html>
------------------------------------------------------------------
<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib uri="sitemesh-decorator" prefix="decorator" %>
<html>
<head>
<title><decorator:title default="裝飾器頁面..." /></title>
<decorator:head />
</head>
<body>
<p><font color="green">this is style2's header</font></p>
<hr>
<decorator:body />
<hr>
<p><font color="green">this is style2's footer</font></p>
</body>
</html>
------------------------------------------------------------------
<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib uri="sitemesh-decorator" prefix="decorator" %>
<html>
<head>
<title><decorator:title default="裝飾器頁面..." /></title>
<decorator:head />
</head>
<body>
<p><font color="blue">this is style3's header</font></p>
<hr>
<decorator:body />
<hr>
<p><font color="blue">this is style3's footer</font></p>
</body>
</html>
------------------------------------------------------------------
再次訪問
http://localhost:8080/sitemesh/index.jsp
http://localhost:8080/sitemesh/style2/index.jsp
http://localhost:8080/sitemesh/login/style3/index.jsp
http://localhost:8080/sitemesh/shared/index.jsp
看到變化了吧。這只是個簡單的展示，仔細思考一下你的需求，你能作出更好的布局方式。
sitemesh真不錯。重要是學習簡單20分種就搞定了
struts.action.extension
The URL extension to use to determine if the request is meant for a Struts action
用URL擴展名來確定是否這個請求是被用作Struts action，其實也就是設置 action的后綴，例如login.do的'do'字。
struts.configuration
The org.apache.struts2.config.Configuration implementation class
org.apache.struts2.config.Configuration接口名
struts.configuration.files
A list of configuration files automatically loaded by Struts
struts自動加載的一個配置文件列表
struts.configuration.xml.reload
Whether to reload the XML configuration or not
是否加載xml配置(true,false)
struts.continuations.package
The package containing actions that use Rife continuations
含有actions的完整連續的package名稱
struts.custom.i18n.resources
Location of additional localization properties files to load
加載附加的國際化屬性文件（不包含.properties后綴）
struts.custom.properties
Location of additional configuration properties files to load
加載附加的配置文件的位置
struts.devMode
Whether Struts is in development mode or not
是否為struts開發模式
struts.dispatcher.parametersWorkaround
Whether to use a Servlet request parameter workaround necessary for some versions of WebLogic
（某些版本的weblogic專用）是否使用一個servlet請求參數工作區（PARAMETERSWORKAROUND）
struts.enable.DynamicMethodInvocation
Allows one to disable dynamic method invocation from the URL
允許動態方法調用
struts.freemarker.manager.classname
The org.apache.struts2.views.freemarker.FreemarkerManager implementation class
org.apache.struts2.views.freemarker.FreemarkerManager接口名
struts.i18n.encoding
The encoding to use for localization messages
國際化信息內碼
struts.i18n.reload
Whether the localization messages should automatically be reloaded
是否國際化信息自動加載
struts.locale
The default locale for the Struts application
默認的國際化地區信息
struts.mapper.class
The org.apache.struts2.dispatcher.mapper.ActionMapper implementation class
org.apache.struts2.dispatcher.mapper.ActionMapper接口
struts.multipart.maxSize
The maximize size of a multipart request (file upload)
multipart請求信息的最大尺寸（文件上傳用）
struts.multipart.parser
The org.apache.struts2.dispatcher.multipart.MultiPartRequest parser implementation for a multipart request (file upload)
專為multipart請求信息使用的org.apache.struts2.dispatcher.multipart.MultiPartRequest解析器接口（文件上傳用）
struts.multipart.saveDir
The directory to use for storing uploaded files
設置存儲上傳文件的目錄夾
struts.objectFactory
The com.opensymphony.xwork2.ObjectFactory implementation class
com.opensymphony.xwork2.ObjectFactory接口（spring）
struts.objectFactory.spring.autoWire
Whether Spring should autoWire or not
是否自動綁定Spring
struts.objectFactory.spring.useClassCache
Whether Spring should use its class cache or not
是否spring應該使用自身的cache
struts.objectTypeDeterminer
The com.opensymphony.xwork2.util.ObjectTypeDeterminer implementation class
com.opensymphony.xwork2.util.ObjectTypeDeterminer接口
struts.serve.static.browserCache
If static content served by the Struts filter should set browser caching header properties or not
是否struts過濾器中提供的靜態內容應該被瀏覽器緩存在頭部屬性中
struts.serve.static
Whether the Struts filter should serve static content or not
是否struts過濾器應該提供靜態內容
struts.tag.altSyntax
Whether to use the alterative syntax for the tags or not
是否可以用替代的語法替代tags
struts.ui.templateDir
The directory containing UI templates
UI templates的目錄夾
struts.ui.theme
The default UI template theme
默認的UI template主題
struts.url.http.port
The HTTP port used by Struts URLs
設置http端口
struts.url.https.port
The HTTPS port used by Struts URLs
設置https端口
struts.url.includeParams
The default includeParams method to generate Struts URLs
在url中產生 默認的includeParams
struts.velocity.configfile
The Velocity configuration file path
velocity配置文件路徑
struts.velocity.contexts
List of Velocity context names
velocity的context列表
struts.velocity.manager.classname
org.apache.struts2.views.velocity.VelocityManager implementation class
org.apache.struts2.views.velocity.VelocityManager接口名
struts.velocity.toolboxlocation
The location of the Velocity toolbox
velocity工具盒的位置
struts.xslt.nocache
Whether or not XSLT templates should not be cached
是否XSLT模版應該被緩存