java.lang.Object
org.apache.struts.action.Action
org.apache.struts.actions.DispatchAction
org.apache.struts.actions.LookupDispatchAction(Struts1.1)
org.apache.struts.actions.EventDispatchAction(Struts1.2.9)
org.apache.struts.actions.MappingDispatchAction(Struts1.2)
DispatchAction
public abstract class DispatchAction extends Action
這是一個抽象的Action,它會根據request 中的parameter來執行相應的方法。通個這個Action類可以將不同的Action集中到一個Action文件中來。
struts-config.xml：
<action path="/subscription" type="org.example.SubscriptionAction" name="subscriptionForm" scope="request" input="/subscription.jsp" parameter="method"/>
在Action中要有相應的方法：
public class SubscriptionAction extends DispatchAction {
public ActionForward delete(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward insert(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward update(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
}
然后可以通過這樣的方法來訪問你的程序：
http://localhost:8080/myapp/subscription.do?method=delete
http://localhost:8080/myapp/subscription.do?method=insert
http://localhost:8080/myapp/subscription.do?method=update
如果parameter中參數為空，則調用Action中的unspecified方法
LookupDispatchAction
public abstract class LookupDispatchAction extends DispatchAction
通過這個Action抽象類繼承DispatchAction，它的相應方法的執行由ActionMapping中parameter屬性決定。每個動作實際上就是<html:submit>標簽的property屬性值。它適合在一個form中有很多按鈕，按不同的按鈕則執行不同的操作。
struts-config.xml：
<action path="/subscription" type="org.example.SubscriptionAction" name="subscriptionForm" scope="request"
input="/subscription.jsp" parameter="method"/>
ApplicationResources.properties：
button.add=Add Record
button.delete=Delete Record
JSP：
<%@ page pageEncoding="GBK"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<html>
<head>
<title>多提交演示</title>
</head>
<body>
<html:form action="subscription">
<html:submit property="method">
<bean:message key="button.add"/>
</html:submit>
<html:submit property="method">
<bean:message key="button.delete"/>
</html:submit>
</html:form>
</body>
</html>
在Action中必須實現getKeyMethodMap方法：
public class SubscriptionAction extends LookupDispatchAction {
protected Map getKeyMethodMap() {
Map map = new HashMap();
map.put("button.add", "add");
map.put("button.delete", "delete");
return map;
}
public ActionForward add(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward delete(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
}
EventDispatchAction
public class EventDispatchAction extends DispatchAction
通過這個Action抽象類繼承DispatchAction，它的相應方法的執行由ActionMapping中parameter屬性指定多個動作，中間用逗號(,)分隔。每個動作實際上就是<html:submit>標簽的property屬性值。它適合在一個form中有很多按鈕，按不同的按鈕則執行不同的操作。
struts-config.xml：
(parameter中的"recalc=recalculate"意思為<html:submit>標簽的property屬性值為recalc調用recalculate方法，出于安全考慮能夠隱藏后臺的業務方法名。"defaule=save"這是可選的，沒有配置property屬性的<html:submit>標簽干洗機將調用defaule中設置的方法名，如果defaule沒有指定任何參數，則調用Action中的unspecified方法)
<action path="/subscription" type="org.example.SubscriptionAction" name="subscriptionForm" scope="request"
input="/subscription.jsp" parameter="save,back,recalc=recalculate,default=save"/>
JSP：
<%@ page pageEncoding="GBK"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<html>
<head>
<title>多提交演示</title>
</head>
<body>
<html:form action="subscription">
<html:submit property="save" value="保存"/>
<html:submit property="back" value="后退"/>
<html:submit property="recalc" value="重新計算"/>
</html:form>
</body>
</html>
在Action中要有相應的方法：
public class SubscriptionAction extends LookupDispatchAction {
public ActionForward save(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward back(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward recalculate(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
}
MappingDispatchAction
public class MappingDispatchAction extends DispatchAction
它的相應方法的執行由ActionMapping中parameter名決定,注意這里和LookupDispatchAction不同，LookupDispatchAction的相應方法的執行由ActionMapping中parameter屬性決定。
struts-config.xml：
<action path="/createSubscription" type="org.example.SubscriptionAction" parameter="create">
<forward name="success" path="/createSubscription.jsp"/>
</action>
<action path="/editSubscription" type="org.example.SubscriptionAction" parameter="edit">
<forward name="success" path="/editSubscription.jsp"/>
</action>
<action path="/saveSubscription" type="org.example.SubscriptionAction" parameter="save"
name="subscriptionForm" validate="true" input="/editSubscription.jsp" scope="request">
<forward name="success" path="/savedSubscription.jsp"/>
</action>
<action path="/deleteSubscription" type="org.example.SubscriptionAction" name="subscriptionForm"
scope="request" input="/subscription.jsp" parameter="delete">
<forward name="success" path="/deletedSubscription.jsp"/>
</action>
<action path="/listSubscriptions" type="org.example.SubscriptionAction" parameter="list">
<forward name="success" path="/subscriptionList.jsp"/>
</action>
在Action中要有相應的方法：
public class SubscriptionAction extends MappingDispatchAction {
public ActionForward create(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward edit(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward save(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward delete(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
public ActionForward list(ActionMapping mapping, ActionForm form,
HttpServletRequest request,
HttpServletResponse response) throws Exception {}
}