struct2中struct.xml中package继承的文件和访问url时struct可以解析一般路径和.action文件的路径

1 首先介绍继承extend的struct-default,先找到structs2-core-2.3.32的jar文件，打开找到一个名字叫做struct-default的xml文件。
打开

配置文件内容`

<?xml version="1.0" encoding="UTF-8" ?>
<!--
/*
 * $Id$
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
-->

<!--
    When declaring beans in this file you must either use name="struts" or don't name the bean at all.

    The name="struts" must be used when alias was defined in {@link org.apache.struts2.config.DefaultBeanSelectionProvider} -
    it is then the default bean's name and {@link org.apache.struts2.config.DefaultBeanSelectionProvider} links name "struts"
    with "default" (aliasing it)

    If name won't be defined then the "default" value will be used {@link com.opensymphony.xwork2.inject.Container#DEFAULT_NAME}
    and {@link com.opensymphony.xwork2.inject.Inject}
-->
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

    <constant name="struts.excludedClasses"
              value="
                java.lang.Object,
                java.lang.Runtime,
                java.lang.System,
                java.lang.Class,
                java.lang.ClassLoader,
                java.lang.Shutdown,
                java.lang.ProcessBuilder,
                ognl.OgnlContext,
                ognl.ClassResolver,
                ognl.TypeConverter,
                ognl.MemberAccess,
                ognl.DefaultMemberAccess,
                com.opensymphony.xwork2.ognl.SecurityMemberAccess,
                com.opensymphony.xwork2.ActionContext" />

    <!-- this must be valid regex, each '.' in package name must be escaped! -->
    <!-- it's more flexible but slower than simple string comparison -->
    <!-- constant name="struts.excludedPackageNamePatterns" value="^java\.lang\..*,^ognl.*,^(?!javax\.servlet\..+)(javax\..+)" / -->

    <!-- this is simpler version of the above used with string comparison -->
    <constant name="struts.excludedPackageNames" value="java.lang.,ognl,javax" />

    <bean class="com.opensymphony.xwork2.ObjectFactory" name="struts"/>
    <bean type="com.opensymphony.xwork2.factory.ResultFactory" name="struts" class="org.apache.struts2.factory.StrutsResultFactory" />
    <bean type="com.opensymphony.xwork2.factory.ActionFactory" name="struts" class="com.opensymphony.xwork2.factory.DefaultActionFactory" />
    <bean type="com.opensymphony.xwork2.factory.ConverterFactory" name="struts" class="com.opensymphony.xwork2.factory.DefaultConverterFactory" />
    <bean type="com.opensymphony.xwork2.factory.InterceptorFactory" name="struts" class="com.opensymphony.xwork2.factory.DefaultInterceptorFactory" />
    <bean type="com.opensymphony.xwork2.factory.ValidatorFactory" name="struts" class="com.opensymphony.xwork2.factory.DefaultValidatorFactory" />
    <bean type="com.opensymphony.xwork2.factory.UnknownHandlerFactory" name="struts" class="com.opensymphony.xwork2.factory.DefaultUnknownHandlerFactory" />

    <bean type="com.opensymphony.xwork2.FileManager" class="com.opensymphony.xwork2.util.fs.DefaultFileManager" name="system" scope="singleton"/>
    <bean type="com.opensymphony.xwork2.FileManagerFactory" class="com.opensymphony.xwork2.util.fs.DefaultFileManagerFactory" name="struts" scope="singleton"/>

    <bean type="com.opensymphony.xwork2.ActionProxyFactory" name="struts" class="org.apache.struts2.impl.StrutsActionProxyFactory"/>
    <bean type="com.opensymphony.xwork2.ActionProxyFactory" name="prefix" class="org.apache.struts2.impl.PrefixBasedActionProxyFactory"/>

    <bean type="com.opensymphony.xwork2.conversion.ObjectTypeDeterminer" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultObjectTypeDeterminer"/>

    <bean type="com.opensymphony.xwork2.util.PatternMatcher" name="struts" class="com.opensymphony.xwork2.util.WildcardHelper" />
    <bean type="com.opensymphony.xwork2.util.PatternMatcher" name="namedVariable" class="com.opensymphony.xwork2.util.NamedVariablePatternMatcher"/>
    <bean type="com.opensymphony.xwork2.util.PatternMatcher" name="regex" class="org.apache.struts2.util.RegexPatternMatcher"/>

    <bean type="org.apache.struts2.util.ContentTypeMatcher" name="struts" class="org.apache.struts2.util.DefaultContentTypeMatcher"/>

    <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="struts" class="org.apache.struts2.dispatcher.mapper.DefaultActionMapper" />
    <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="composite" class="org.apache.struts2.dispatcher.mapper.CompositeActionMapper" />
    <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="restful" class="org.apache.struts2.dispatcher.mapper.RestfulActionMapper" />
    <bean type="org.apache.struts2.dispatcher.mapper.ActionMapper" name="restful2" class="org.apache.struts2.dispatcher.mapper.Restful2ActionMapper" />

    <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="jakarta" class="org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest" scope="default"/>
    <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="jakarta-stream" class="org.apache.struts2.dispatcher.multipart.JakartaStreamMultiPartRequest" scope="default"/>

    <bean type="org.apache.struts2.views.TagLibraryDirectiveProvider" name="s" class="org.apache.struts2.views.DefaultTagLibrary" />
    <bean type="org.apache.struts2.views.TagLibraryModelProvider" name="s" class="org.apache.struts2.views.DefaultTagLibrary" />

    <bean class="org.apache.struts2.views.freemarker.FreemarkerThemeTemplateLoader" />
    <bean class="org.apache.struts2.views.freemarker.FreemarkerManager" name="struts" />
    <bean class="org.apache.struts2.views.velocity.VelocityManager" name="struts" optional="true" />

    <bean class="org.apache.struts2.components.template.TemplateEngineManager" />
    <bean type="org.apache.struts2.components.template.TemplateEngine" name="ftl" class="org.apache.struts2.components.template.FreemarkerTemplateEngine" />
    <bean type="org.apache.struts2.components.template.TemplateEngine" name="vm" class="org.apache.struts2.components.template.VelocityTemplateEngine" />
    <bean type="org.apache.struts2.components.template.TemplateEngine" name="jsp" class="org.apache.struts2.components.template.JspTemplateEngine" />

    <bean type="com.opensymphony.xwork2.conversion.impl.XWorkConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.XWorkConverter" />

    <bean type="com.opensymphony.xwork2.conversion.ConversionPropertiesProcessor" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultConversionPropertiesProcessor" />
    <bean type="com.opensymphony.xwork2.conversion.ConversionFileProcessor" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultConversionFileProcessor" />
    <bean type="com.opensymphony.xwork2.conversion.ConversionAnnotationProcessor" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultConversionAnnotationProcessor" />
    <bean type="com.opensymphony.xwork2.conversion.TypeConverterCreator" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultTypeConverterCreator" />
    <bean type="com.opensymphony.xwork2.conversion.TypeConverterHolder" name="struts" class="com.opensymphony.xwork2.conversion.impl.DefaultTypeConverterHolder" />

    <bean class="com.opensymphony.xwork2.conversion.impl.XWorkBasicConverter" />

    <bean type="com.opensymphony.xwork2.conversion.impl.CollectionConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.CollectionConverter" scope="singleton"/>
    <bean type="com.opensymphony.xwork2.conversion.impl.ArrayConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.ArrayConverter" scope="singleton"/>
    <bean type="com.opensymphony.xwork2.conversion.impl.DateConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.DateConverter" scope="singleton"/>
    <bean type="com.opensymphony.xwork2.conversion.impl.NumberConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.NumberConverter" scope="singleton"/>
    <bean type="com.opensymphony.xwork2.conversion.impl.StringConverter" name="struts" class="com.opensymphony.xwork2.conversion.impl.StringConverter" scope="singleton"/>

    <bean type="com.opensymphony.xwork2.TextProvider" name="struts" class="com.opensymphony.xwork2.TextProviderSupport" scope="default" />
    <bean type="com.opensymphony.xwork2.LocaleProvider" name="struts" class="com.opensymphony.xwork2.DefaultLocaleProvider" scope="singleton" />

    <bean type="org.apache.struts2.components.UrlRenderer" name="struts" class="org.apache.struts2.components.ServletUrlRenderer"/>
    <bean type="org.apache.struts2.views.util.UrlHelper" name="struts" class="org.apache.struts2.views.util.DefaultUrlHelper"/>

    <bean type="com.opensymphony.xwork2.util.ValueStackFactory" name="struts" class="com.opensymphony.xwork2.ognl.OgnlValueStackFactory" />
    <bean type="com.opensymphony.xwork2.util.reflection.ReflectionProvider" name="struts" class="com.opensymphony.xwork2.ognl.OgnlReflectionProvider" />
    <bean type="com.opensymphony.xwork2.util.reflection.ReflectionContextFactory" name="struts" class="com.opensymphony.xwork2.ognl.OgnlReflectionContextFactory" />

    <bean type="com.opensymphony.xwork2.TextProvider" name="system" class="com.opensymphony.xwork2.DefaultTextProvider" />
    <bean type="com.opensymphony.xwork2.conversion.NullHandler" name="java.lang.Object" class="com.opensymphony.xwork2.conversion.impl.InstantiatingNullHandler" />

    <bean type="com.opensymphony.xwork2.validator.ActionValidatorManager" name="struts" class="com.opensymphony.xwork2.validator.AnnotationActionValidatorManager" />
    <bean type="com.opensymphony.xwork2.validator.ActionValidatorManager" name="no-annotations" class="com.opensymphony.xwork2.validator.DefaultActionValidatorManager" />

    <bean type="com.opensymphony.xwork2.validator.ValidatorFactory" class="com.opensymphony.xwork2.validator.DefaultValidatorFactory"/>
    <bean type="com.opensymphony.xwork2.validator.ValidatorFileParser" class="com.opensymphony.xwork2.validator.DefaultValidatorFileParser" />

    <bean class="com.opensymphony.xwork2.ognl.OgnlUtil" />

    <bean type="com.opensymphony.xwork2.util.TextParser" name="struts" class="com.opensymphony.xwork2.util.OgnlTextParser" scope="singleton"/>

    <bean type="ognl.PropertyAccessor" name="com.opensymphony.xwork2.util.CompoundRoot" class="com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.lang.Object" class="com.opensymphony.xwork2.ognl.accessor.ObjectAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.Iterator" class="com.opensymphony.xwork2.ognl.accessor.XWorkIteratorPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.Enumeration" class="com.opensymphony.xwork2.ognl.accessor.XWorkEnumerationAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.List" class="com.opensymphony.xwork2.ognl.accessor.XWorkListPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.Set" class="com.opensymphony.xwork2.ognl.accessor.XWorkCollectionPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.Map" class="com.opensymphony.xwork2.ognl.accessor.XWorkMapPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.Collection" class="com.opensymphony.xwork2.ognl.accessor.XWorkCollectionPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="com.opensymphony.xwork2.ognl.ObjectProxy" class="com.opensymphony.xwork2.ognl.accessor.ObjectProxyPropertyAccessor" />

    <bean type="ognl.MethodAccessor" name="java.lang.Object" class="com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor" />
    <bean type="ognl.MethodAccessor" name="com.opensymphony.xwork2.util.CompoundRoot" class="com.opensymphony.xwork2.ognl.accessor.CompoundRootAccessor" />

    <bean class="org.apache.struts2.views.jsp.ui.OgnlTool" />

    <bean type="org.apache.struts2.dispatcher.StaticContentLoader" class="org.apache.struts2.dispatcher.DefaultStaticContentLoader" name="struts" />
    <bean type="com.opensymphony.xwork2.UnknownHandlerManager" class="com.opensymphony.xwork2.DefaultUnknownHandlerManager" name="struts" />

    <bean type="org.apache.struts2.dispatcher.DispatcherErrorHandler" name="struts" class="org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler" />
    
    <constant name="struts.dispatcher.errorHandler" value="struts" />

    <!--  Silly workarounds for OGNL since there is currently no way to flush its internal caches -->
    <bean type="ognl.PropertyAccessor" name="java.util.ArrayList" class="com.opensymphony.xwork2.ognl.accessor.XWorkListPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.HashSet" class="com.opensymphony.xwork2.ognl.accessor.XWorkCollectionPropertyAccessor" />
    <bean type="ognl.PropertyAccessor" name="java.util.HashMap" class="com.opensymphony.xwork2.ognl.accessor.XWorkMapPropertyAccessor" />

    <bean type="com.opensymphony.xwork2.security.ExcludedPatternsChecker" name="struts" class="com.opensymphony.xwork2.security.DefaultExcludedPatternsChecker" scope="default" />
    <bean type="com.opensymphony.xwork2.security.AcceptedPatternsChecker" name="struts" class="com.opensymphony.xwork2.security.DefaultAcceptedPatternsChecker" scope="default" />

    <package name="struts-default" abstract="true">
        <result-types>
            <result-type name="chain" class="com.opensymphony.xwork2.ActionChainResult"/>
            <result-type name="dispatcher" class="org.apache.struts2.dispatcher.ServletDispatcherResult" default="true"/>
            <result-type name="freemarker" class="org.apache.struts2.views.freemarker.FreemarkerResult"/>
            <result-type name="httpheader" class="org.apache.struts2.dispatcher.HttpHeaderResult"/>
            <result-type name="redirect" class="org.apache.struts2.dispatcher.ServletRedirectResult"/>
            <result-type name="redirectAction" class="org.apache.struts2.dispatcher.ServletActionRedirectResult"/>
            <result-type name="stream" class="org.apache.struts2.dispatcher.StreamResult"/>
            <result-type name="velocity" class="org.apache.struts2.dispatcher.VelocityResult"/>
            <result-type name="xslt" class="org.apache.struts2.views.xslt.XSLTResult"/>
            <result-type name="plainText" class="org.apache.struts2.dispatcher.PlainTextResult" />
            <result-type name="postback" class="org.apache.struts2.dispatcher.PostbackResult" />
        </result-types>

        <interceptors>
            <interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/>
            <interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/>
            <interceptor name="chain" class="com.opensymphony.xwork2.interceptor.ChainingInterceptor"/>
            <interceptor name="conversionError" class="org.apache.struts2.interceptor.StrutsConversionErrorInterceptor"/>
            <interceptor name="cookie" class="org.apache.struts2.interceptor.CookieInterceptor"/>
            <interceptor name="cookieProvider" class="org.apache.struts2.interceptor.CookieProviderInterceptor"/>
            <interceptor name="clearSession" class="org.apache.struts2.interceptor.ClearSessionInterceptor" />
            <interceptor name="createSession" class="org.apache.struts2.interceptor.CreateSessionInterceptor" />
            <interceptor name="debugging" class="org.apache.struts2.interceptor.debugging.DebuggingInterceptor" />
            <interceptor name="execAndWait" class="org.apache.struts2.interceptor.ExecuteAndWaitInterceptor"/>
            <interceptor name="exception" class="com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor"/>
            <interceptor name="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>
            <interceptor name="i18n" class="com.opensymphony.xwork2.interceptor.I18nInterceptor"/>
            <interceptor name="logger" class="com.opensymphony.xwork2.interceptor.LoggingInterceptor"/>
            <interceptor name="modelDriven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>
            <interceptor name="scopedModelDriven" class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>
            <interceptor name="params" class="com.opensymphony.xwork2.interceptor.ParametersInterceptor"/>
            <interceptor name="actionMappingParams" class="org.apache.struts2.interceptor.ActionMappingParametersInteceptor"/>
            <interceptor name="prepare" class="com.opensymphony.xwork2.interceptor.PrepareInterceptor"/>
            <interceptor name="staticParams" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>
            <interceptor name="scope" class="org.apache.struts2.interceptor.ScopeInterceptor"/>
            <interceptor name="servletConfig" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>
            <interceptor name="timer" class="com.opensymphony.xwork2.interceptor.TimerInterceptor"/>
            <interceptor name="token" class="org.apache.struts2.interceptor.TokenInterceptor"/>
            <interceptor name="tokenSession" class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/>
            <interceptor name="validation" class="org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor"/>
            <interceptor name="workflow" class="com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor"/>
            <interceptor name="store" class="org.apache.struts2.interceptor.MessageStoreInterceptor" />
            <interceptor name="checkbox" class="org.apache.struts2.interceptor.CheckboxInterceptor" />
            <interceptor name="datetime" class="org.apache.struts2.interceptor.DateTextFieldInterceptor" />
            <interceptor name="profiling" class="org.apache.struts2.interceptor.ProfilingActivationInterceptor" />
            <interceptor name="roles" class="org.apache.struts2.interceptor.RolesInterceptor" />
            <interceptor name="annotationWorkflow" class="com.opensymphony.xwork2.interceptor.annotations.AnnotationWorkflowInterceptor" />
            <interceptor name="multiselect" class="org.apache.struts2.interceptor.MultiselectInterceptor" />
            <interceptor name="deprecation" class="org.apache.struts2.interceptor.DeprecationInterceptor" />

            <!-- Basic stack -->
            <interceptor-stack name="basicStack">
                <interceptor-ref name="exception"/>
                <interceptor-ref name="servletConfig"/>
                <interceptor-ref name="prepare"/>
                <interceptor-ref name="checkbox"/>
                <interceptor-ref name="datetime"/>
                <interceptor-ref name="multiselect"/>
                <interceptor-ref name="actionMappingParams"/>
                <interceptor-ref name="params"/>
                <interceptor-ref name="conversionError"/>
                <interceptor-ref name="deprecation"/>
            </interceptor-stack>

            <!-- Sample validation and workflow stack -->
            <interceptor-stack name="validationWorkflowStack">
                <interceptor-ref name="basicStack"/>
                <interceptor-ref name="validation"/>
                <interceptor-ref name="workflow"/>
            </interceptor-stack>

            <!-- Sample file upload stack -->
            <interceptor-stack name="fileUploadStack">
                <interceptor-ref name="fileUpload"/>
                <interceptor-ref name="basicStack"/>
            </interceptor-stack>

            <!-- Sample model-driven stack  -->
            <interceptor-stack name="modelDrivenStack">
                <interceptor-ref name="modelDriven"/>
                <interceptor-ref name="basicStack"/>
            </interceptor-stack>

            <!-- Sample action chaining stack -->
            <interceptor-stack name="chainStack">
                <interceptor-ref name="chain"/>
                <interceptor-ref name="basicStack"/>
            </interceptor-stack>

            <!-- Sample i18n stack -->
            <interceptor-stack name="i18nStack">
                <interceptor-ref name="i18n"/>
                <interceptor-ref name="basicStack"/>
            </interceptor-stack>

            <!-- An example of the paramsPrepareParams trick. This stack
                 is exactly the same as the defaultStack, except that it
                 includes one extra interceptor before the prepare interceptor:
                 the params interceptor.

                 This is useful for when you wish to apply parameters directly
                 to an object that you wish to load externally (such as a DAO
                 or database or service layer), but can't load that object
                 until at least the ID parameter has been loaded. By loading
                 the parameters twice, you can retrieve the object in the
                 prepare() method, allowing the second params interceptor to
                 apply the values on the object. -->
            <interceptor-stack name="paramsPrepareParamsStack">
                <interceptor-ref name="exception"/>
                <interceptor-ref name="alias"/>
                <interceptor-ref name="i18n"/>
                <interceptor-ref name="checkbox"/>
                <interceptor-ref name="datetime"/>
                <interceptor-ref name="multiselect"/>
                <interceptor-ref name="params"/>
                <interceptor-ref name="servletConfig"/>
                <interceptor-ref name="prepare"/>
                <interceptor-ref name="chain"/>
                <interceptor-ref name="modelDriven"/>
                <interceptor-ref name="fileUpload"/>
                <interceptor-ref name="staticParams"/>
                <interceptor-ref name="actionMappingParams"/>
                <interceptor-ref name="params"/>
                <interceptor-ref name="conversionError"/>
                <interceptor-ref name="validation">
                    <param name="excludeMethods">input,back,cancel,browse</param>
                </interceptor-ref>
                <interceptor-ref name="workflow">
                    <param name="excludeMethods">input,back,cancel,browse</param>
                </interceptor-ref>
            </interceptor-stack>

            <!-- A complete stack with all the common interceptors in place.
                 Generally, this stack should be the one you use, though it
                 may do more than you need. Also, the ordering can be
                 switched around (ex: if you wish to have your servlet-related
                 objects applied before prepare() is called, you'd need to move
                 servletConfig interceptor up.

                 This stack also excludes from the normal validation and workflow
                 the method names input, back, and cancel. These typically are
                 associated with requests that should not be validated.
                 -->
            <interceptor-stack name="defaultStack">
                <interceptor-ref name="exception"/>
                <interceptor-ref name="alias"/>
                <interceptor-ref name="servletConfig"/>
                <interceptor-ref name="i18n"/>
                <interceptor-ref name="prepare"/>
                <interceptor-ref name="chain"/>
                <interceptor-ref name="scopedModelDriven"/>
                <interceptor-ref name="modelDriven"/>
                <interceptor-ref name="fileUpload"/>
                <interceptor-ref name="checkbox"/>
                <interceptor-ref name="datetime"/>
                <interceptor-ref name="multiselect"/>
                <interceptor-ref name="staticParams"/>
                <interceptor-ref name="actionMappingParams"/>
                <interceptor-ref name="params"/>
                <interceptor-ref name="conversionError"/>
                <interceptor-ref name="validation">
                    <param name="excludeMethods">input,back,cancel,browse</param>
                </interceptor-ref>
                <interceptor-ref name="workflow">
                    <param name="excludeMethods">input,back,cancel,browse</param>
                </interceptor-ref>
                <interceptor-ref name="debugging"/>
                <interceptor-ref name="deprecation"/>
            </interceptor-stack>

            <!-- The completeStack is here for backwards compatibility for
                 applications that still refer to the defaultStack by the
                 old name -->
            <interceptor-stack name="completeStack">
                <interceptor-ref name="defaultStack"/>
            </interceptor-stack>

            <!-- Sample execute and wait stack.
                 Note: execAndWait should always be the *last* interceptor. -->
            <interceptor-stack name="executeAndWaitStack">
                <interceptor-ref name="execAndWait">
                    <param name="excludeMethods">input,back,cancel</param>
                </interceptor-ref>
                <interceptor-ref name="defaultStack"/>
                <interceptor-ref name="execAndWait">
                    <param name="excludeMethods">input,back,cancel</param>
                </interceptor-ref>
            </interceptor-stack>

       </interceptors>

        <default-interceptor-ref name="defaultStack"/>

        <default-class-ref class="com.opensymphony.xwork2.ActionSupport" />
    </package>

</struts>

我们可以看到有拦截器和结果映射和拦截器栈。最后一个默认使用的com.opensymphony.xwork2.ActionSupport，我们在使用action时不写就默认为这个类，并通过反射调用execute方法。
它的package报名为struc-default就是我们默认需要继承的包。在action标签时，如果引用自己的class类，方法属性method省去时，必须要有execute方法，返回值为success字符串。

2 struct可以解析.action后缀路径的问题
在corejar文件下，我们可以看到有一个default.properties文件，它文件中定义了解析的后缀为action和没有后缀的

同时它还包含文件上传等文件默认配置