动态表单和定制化Action

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我是靠谱客的博主迷你招牌，最近开发中收集的这篇文章主要介绍动态表单和定制化Action ，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

1. DynaActionForm
（1）为什么用动态表单
如果用ActionForm，每个页面的表单都要写一个ActionForm，每当表单修改时ActionForm都要修改和重新编译
DynaActionForm直接在配置文件中配置，不用编码，便于修改

（2）使用DynaActionForm的方法：
* 在struts-config.xml的<form-beans>标签中添加：

<form-bean name= "DynaForm" type= "org.apache.struts.action.DynaActionForm" dynamic= "true" >
<form-property name= "userName" type= "java.lang.String" />
</form-bean>

* <action>的 name="DynaForm"
* 在Action中如果要访问DynaActionForm
String userName = ( String )( ( DynaActionForm )form ).get( "userName" );

因为DynaActionForm是用map实现

2. 定制化Action -- DispatchAction

（1）应用场合：不同页面，相同表单，执行不同的方法
（2）使用方法：
* 写一个类继承DispatchAction, 为每个需要的服务写一个方法
* 不用重写 execute(), 因为DispatchAction提供execute()
（3）例子：
* 在resource file 中添加：

account=account no.
amt=amount

submit.deposit=deposit
submit.withdraw=withdraw

* 写两个jsp页面

//dispatch_dp.jsp
<%@ page contentType="text/html;charset=UTF-8" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>

<html:errors/>

<html:form action="/dpwd.do?method=deposit">
<bean:message key="account"/>
<html:text property="account" size="16" maxlength="16"/><br>

<bean:message key="amt" />
<html:text property="amount" size="16" maxlength="16"/><br>

<html:submit property="submit" value="deposit"/>
</html:form>

//dispatch_wd.jsp
<%@ page contentType="text/html;charset=UTF-8" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>

<html:errors/>

<html:form action="/dpwd.do?method=withdraw">
<bean:message key="account"/>
<html:text property="account" size="16" maxlength="16"/><br>

<bean:message key="amt" />
<html:text property="amount" size="16" maxlength="16"/><br>

<html:submit property="submit" value="withdraw"/>
</html:form>

* 在struts-config.xml配置<form-bean>
<form-bean name="DorWForm" type="org.apache.struts.validator.DynaValidatorForm" dynamic="true">
<form-property name="account" type="java.lang.String" />
<form-property name="amount" type="java.lang.String" />
</form-bean>

* 写Action

//AccountAction
package hello;

import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.*;
import org.apache.struts.actions.*;
import org.apache.struts.util.*;

public final class AccountAction extends DispatchAction{
public ActionForward deposit( ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response ) throws Exception {

request.setAttribute( "method", "deposit" );
return mapping.findForward( "accountok" );
}

public ActionForward withdraw( ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response ) throws Exception {

request.setAttribute( "method", "withdraw" );
return mapping.findForward( "accountok" );
}
}

* 在struts-config.xml配置<action>
<action path = "/dpwd"
type = "hello.AccountAction"
name = "DorWForm"
scope = "request"
validate = "false"
input = "/dispatch_dp.jsp"
parameter="method"
>
<forward name="accountok" path="/accountok.jsp" />
</action>

* 写accountok.jsp
method :<%= request.getAttribute( "method" ) %>
<br>
<h1>ok</h1>

3. 定制化Action -- LookupDispatchAction

（1）应用场合：同一个表单，多个同名submit
（2）使用方法：
* 写一个类继承LookupDispatchAction, 为每个需要的服务写一个方法
* 重写getKeyMethodMap(), map key resource file 中定义的key, map value 是方法名
LookupDispatchAction 是根据submit value去resource file 中找到key, 然后到 map 中找到方法
（3）例子：
* 写dorw.jsp
<%@ page contentType="text/html;charset=UTF-8" %>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>
<%@ taglib uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic" %>

<html:html locale="true">
<head>
<title>
<bean:message key="title"/>
</title>
<html:base/>
</head>

<body>
<html:errors/>

<html:form action="/dow.do" focus="userName">
<bean:message key="account"/>
<html:text property="account" size="16" maxlength="16"/><br>
<bean:message key="amt" />
<html:text property="amount" size="16" maxlength="16"/><br>
<html:submit property="action"><bean:message key="submit.deposit"/></html:submit>
<html:submit property="action"><bean:message key="submit.withdraw"/></html:submit>
</html:form>
</body>
</html:html>

* 写Action
//DepositOrWithdrawAction
package hello;

import javax.servlet.*;
import javax.servlet.http.*;
import org.apache.struts.action.*;
import org.apache.struts.actions.*;
import org.apache.struts.util.*;
import java.util.*;
import java.io.*;

public final class DepositOrWithdrawAction extends