📄 入門 09 - 使用dynaactionform類別 - javaworld@tw.htm
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- saved from url=(0071)http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=483 -->
<HTML><HEAD><TITLE>入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW</TITLE>
<META http-equiv=Content-Type content="text/html; charset=utf-8"><!-- CONFL-BEGIN standardHeader -->
<META http-equiv=Pragma content=no-cache>
<META http-equiv=Expires content=-1>
<SCRIPT language=javascript> var contextPath = '/confluence';</SCRIPT>
<LINK href="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/main-action.css"
type=text/css rel=stylesheet><LINK href="/confluence/images/icons/favicon.ico"
rel="shortcut icon"><LINK href="/confluence/images/icons/favicon.png"
type=image/png rel=icon>
<SCRIPT
src="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/effects.js"></SCRIPT>
<!-- CONF-END standardHeader -->
<META content="MSHTML 6.00.2800.1491" name=GENERATOR></HEAD>
<BODY onload=placeFocus()>
<DIV id=Content>
<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD class=logocell width="60%" rowSpan=2>
<DIV class=spacenametitle><A
href="http://www.javaworld.com.tw/confluence/display/opensrc"><IMG
src="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/confluence_logo.gif"
align=bottom border=0></A> <A
href="http://www.javaworld.com.tw/confluence/display/opensrc">OpenSource
Project</A></DIV></TD>
<TD vAlign=top align=right width="40%">
<TABLE cellSpacing=1 cellPadding=2 align=right bgColor=#ffffff border=0>
<TBODY>
<TR>
<TD class=navItem onmouseover="this.className='navItemOver'"
onclick="window.document.location='/confluence/'"
onmouseout="this.className='navItem'" vAlign=center noWrap
align=middle> <A title="Go to the Confluence Dashboard"
accessKey=h onclick="return false"
href="http://www.javaworld.com.tw/confluence/"><U>H</U>OME</A>
</TD>
<TD class=navItem onmouseover="this.className='navItemOver'"
onclick="window.document.location='/confluence/spaces/listspaces.action'"
onmouseout="this.className='navItem'" vAlign=center noWrap
align=middle> <A title="The spaces available for you"
accessKey=s onclick="return false"
href="http://www.javaworld.com.tw/confluence/spaces/listspaces.action"><U>S</U>PACES</A>
</TD></TR></TBODY></TABLE></TD></TR>
<TR>
<TD vAlign=bottom align=right><SPAN class=smalltext><A
href="http://www.javaworld.com.tw/confluence/login.action?os_destination=/pages/viewpage.action?pageId=483">Log
In</A> </SPAN><A
href="http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=483&decorator=printable"><IMG
title="View a printable version of the current page." height=16
alt="View a printable version of the current page." hspace=1
src="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/print_16.gif"
width=16 align=absMiddle vspace=1 border=0></A> <A
href="http://confluence.atlassian.com/display/DOC"><IMG
title="Get help from the Confluence website." height=16
alt="Get help from the Confluence website." hspace=1
src="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/help_16.gif" width=16
align=absMiddle vspace=1 border=0></A> </TD></TR></TBODY></TABLE><!-- CONF-BEGIN breadcrumbsAndSearch -->
<DIV class=breadcrumbs width="100%">
<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD> Location: <A
href="http://www.javaworld.com.tw/confluence/dashboard.action">Dashboard</A>
> <A
href="http://www.javaworld.com.tw/confluence/spaces/viewspacesummary.action?key=opensrc">opensrc</A>
> <A
href="http://www.javaworld.com.tw/confluence/pages/listpages.action?key=opensrc">Pages</A>
> <A
href="http://www.javaworld.com.tw/confluence/display/opensrc/Home">Home</A>
> <A
href="http://www.javaworld.com.tw/confluence/display/opensrc/Struts">Struts</A>
> <A
href="http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=1958">Struts入門</A>
> <A
href="http://www.javaworld.com.tw/confluence/pages/viewpage.action?pageId=483">入門
09 - 使用DynaActionForm類別</A> </TD>
<FORM name=searchForm action=/confluence/dosearchsite.action
method=get><INPUT type=hidden value=true name=quickSearch>
<TD vAlign=bottom align=right width=200><A style="TEXT-DECORATION: none"
href="http://www.javaworld.com.tw/confluence/searchsite.action"><U>Q</U>uick
<U>Search</U></A>:<INPUT accessKey=q size=10 name=searchQuery.queryString><INPUT type=submit value=Go><BR><IMG height=1
src="入門 09 - 使用DynaActionForm類別 - JAVAWORLD@TW.files/spacer.gif"
width=200></TD></FORM></TR></TBODY></TABLE></DIV><!-- CONF-END breadcrumbsAndSearch -->
<TABLE cellSpacing=0 cellPadding=5 width="100%" border=0>
<TBODY>
<TR>
<TD>
<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0>
<TBODY>
<TR>
<TD class=pagebody vAlign=top>
<DIV class=pageheader><SPAN class=pagetitle>入門 09 -
使用DynaActionForm類別</SPAN> </DIV>
<SCRIPT language=javascript> function toggle(id) { var oldAttachmentVersionsBlock = document.getElementById('attachment' + id); with (oldAttachmentVersionsBlock.style) { if ( display == "none" ) display = "" else display = "none" } var arrowIcon = document.getElementById('arrow' + id); with (arrowIcon) { if (src != null && (src.indexOf('/confluence/images/icons/arrow_closed_active_16.gif') != -1 || src.indexOf('/confluence/images/icons/arrow_closing_active_16.gif') != -1)) { src = '/confluence/images/icons/arrow_opening_active_16.gif'; } else { src = '/confluence/images/icons/arrow_closing_active_16.gif'; } } } </SCRIPT>
<DIV class=pagesubheading>Last changed on Oct 27, 2004 by <A
href="http://www.javaworld.com.tw/confluence/display/~koji">koji
lin</A>
</DIV><!-- page content --> 一個網站中會有許多的表單以供使用者填寫資料，越大型的網站越需要更多的ActionForm物件來應付表單的取值，對於一些表單來說，ActionForm只是單純的設值、取值行為，如果為每一個表單撰寫一個ActionForm，那麼會是一件單純重複且無趣的行為，而且在維護上會更加困難。<BR> 對於一些單純的表單來說，您可以使用DynaActionForm類別，您只要在struct-config.xml中設定好相關的設定，就可以自動生成ActionForm物件，這麼一來您可以集中在struct-config.xml中管理表單物件，也可以省去不是編碼與編譯的工夫。<BR> 下面是使用DynaActionForm的一個例子：
<DIV class=code
style="BORDER-TOP-STYLE: solid; BORDER-RIGHT-STYLE: solid; BORDER-LEFT-STYLE: solid; BORDER-BOTTOM-STYLE: solid">
<DIV class=codeHeader
style="BORDER-BOTTOM-STYLE: solid"><B>struts-config.xml</B></DIV>
<DIV class=codeContent><PRE><struts-config>
<form-beans>
<form-bean
name=<SPAN class=java-quote>"userForm"</SPAN>
type=<SPAN class=java-quote>"org.apache.struts.action.DynaActionForm"</SPAN>>
<form-property
name=<SPAN class=java-quote>"name"</SPAN>
type=<SPAN class=java-quote>"java.lang.<SPAN class=java-object>String</SPAN>"</SPAN>
initial=<SPAN class=java-quote>"nobody"</SPAN>/>
<form-property
name=<SPAN class=java-quote>"password"</SPAN>
type=<SPAN class=java-quote>"java.lang.<SPAN class=java-object>String</SPAN>"</SPAN>
initial=<SPAN class=java-quote>"nopass"</SPAN>/>
</form-bean>
</form-beans>
<global-forwards>
<forward
name=<SPAN class=java-quote>"welcome"</SPAN>
path=<SPAN class=java-quote>"/Welcome.<SPAN class=java-keyword>do</SPAN>"</SPAN>/>
</global-forwards>
<action-mappings>
<action
path=<SPAN class=java-quote>"/Welcome"</SPAN>
type=<SPAN class=java-quote>"org.apache.struts.actions.ForwardAction"</SPAN>
parameter=<SPAN class=java-quote>"/pages/Welcome.jsp"</SPAN>/>
<action
path=<SPAN class=java-quote>"/LoginAction"</SPAN>
type=<SPAN class=java-quote>"onlyfun.caterpillar.LoginAction"</SPAN>
name=<SPAN class=java-quote>"userForm"</SPAN>>
<forward
name=<SPAN class=java-quote>"greeting"</SPAN>
path=<SPAN class=java-quote>"/pages/greeting.jsp"</SPAN>/>
</action>
</action-mappings>
<message-resources parameter=<SPAN class=java-quote>"resources.application"</SPAN>/>
</struts-config></PRE></DIV></DIV><BR> 注意在<form-bean>的type屬性，我們設定使用
org.apache.struts.action.DynaActionForm，而Form的屬性則使用<form-property>
標籤來設定，DymaActionForm的type屬性希望得到的一個Java類別名稱，所以對於基本資料型態如int，必須以
java.lang.Integer作為Wrapper類別包裝。<BR> ActionForm類別的reset()方法預設什麼事都不作，除非您重新定義它，DynaActionForm則預設會將所有的資料重設為Java型態的預設值，例如數字重設為0，而Object則重設為null，您也可以使用initial屬性來設定重設的值。<BR> DynaActionForm同樣也被當作參數傳遞給execute()方法，DynaActionForm使用Map型態的方法來取值，下面的Action類別示範了如何取得DynaActionForm的屬性值：
<DIV class=code
style="BORDER-TOP-STYLE: solid; BORDER-RIGHT-STYLE: solid; BORDER-LEFT-STYLE: solid; BORDER-BOTTOM-STYLE: solid">
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -