1. MappingDispatchAction的作用域LookupAction的作用差不多相同，但是在应用上稍微有些差别。
 
1.Struts-config.xml
                <action path="/mapping-invalid"    
                                type="org.apache.struts.webapp.dispatch.MappingDispatchExampleAction"
                                parameter="doInvalid"
                                name="testForm"
                                scope="request">
                        <exception key="dispatch.NoSuchMethodException"
                                             type="java.lang.NoSuchMethodException"
                                             path="/mapping.jsp"/>
                        <exception key="dispatch.ServletException"
                                             type="javax.servlet.ServletException"
                                             path="/mapping.jsp"/>
                        <forward name="success" path="/mapping.jsp"/>
                </action>
                <action path="/mapping-execute"    
                                type="org.apache.struts.webapp.dispatch.MappingDispatchExampleAction"
                                parameter="execute"
                                name="testForm"
                                scope="request">
                        <exception key="dispatch.NoSuchMethodException"
                                             type="java.lang.NoSuchMethodException"
                                             path="/mapping.jsp"/>
                        <exception key="dispatch.ServletException"
                                             type="javax.servlet.ServletException"
                                             path="/mapping.jsp"/>
                        <forward name="success" path="/mapping.jsp"/>
                </action>
                <action path="/mapping-noparam"    
                                type="org.apache.struts.webapp.dispatch.MappingDispatchExampleAction"
                                name="testForm"
                                scope="request">
                        <exception key="dispatch.ServletException"
                                             type="javax.servlet.ServletException"
                                             path="/mapping.jsp"/>
                        <forward name="success" path="/mapping.jsp"/>
                </action>
 
主要的工作就是在这里。只不过不同的url 都是指到同一个Action中。使用【parameter】参数来表示不同的url 以访问Action中不同的方法，实现不同的业务逻辑。
 
 
2.然后在JSP 前台页面中，分别提交
    <html:form action="mapping-foo" style="display:inline">
                            <html:submit><bean:message key="button.foo.label" /></html:submit>
                    </html:form>
                             
                    <html:form action="mapping-bar" style="display:inline">
                            <html:submit><bean:message key="button.bar.label" /></html:submit>
                    </html:form>
                             
                    <html:form action="mapping-invalid" style="display:inline">
                            <html:submit><bean:message key="button.invalid.label" /></html:submit>
                    </html:form>
                             
                    <html:form action="mapping-execute" style="display:inline">
                            <html:submit><bean:message key="method.execute.label" /></html:submit>
                    </html:form>
                             
                    <html:form action="mapping-noparam" style="display:inline">
                            <html:submit><bean:message key="parameter.missing.label" /></html:submit>
                    </html:form>
 
这跟表单提交的目标地址，实现访问同一个Action中不同的方法。
 
1、发生的异常 和 LookupDispatcherAction、DispatcherAction的异常一致。