Struts2_013_ActionSupport

概述

• com.opensymphony.xwork2.ActionSupport 类是默认的 Action 类.
• struts-default包位置：

struts2-core.jar ==》 struts-default.xml ==》<package name="struts-default" abstract="true">

• ActionSupport类：
  1.在action节点中，如果不写class的值的话，默认就是：com.opensymphony.xwork2.ActionSupport
  2.原因：因为我们继承了struts-default包，其中有这么一句：
  
<default-class-ref class="com.opensymphony.xwork2.ActionSupport" />


  3.action节点中默认的method值是execute，result中默认的name是success，在ActionSupport类中有这个方法，所以可以不写action节点的class、method和result节点的name属性：

public String execute() throws Exception {    return SUCCESS; //public static final String SUCCESS = "success";}

• 在编写 Action 类时, 通常会对这个类进行扩展

    1.实现的接口：        public class ActionSupport implements Action, Validateable, ValidationAware,             TextProvider, LocaleProvider, Serializable    2.关于Action接口：        属性：SUCCESS、NONE、ERROR、INPUT、LOGIN        方法： execute()         说明：我们直接继承ActionSupport,可以直接使用Action类中的属性和方法    3.关于Validateable接口（后面学习）：        方法：valodate        说明：需要对字段进行验证的时候可以使用    4.关于ValidationAware接口（后面学习）：        属性：包括字段级别的错误消息属性和Action级别的错误消息的属性        方法：包括字段级别的错误消息属性和Action级别的错误消息的方法        说明：接受和显示错误消息的时候可以使用    5.关于TextProvider接口（后面学习）、LocaleProvider接口（后面学习）：        说明：后面做国际化的时候使用

• 继承ActionSupport的好处：
  可以不单独的去实现上面的那些接口，直接继承就行。

• struts-default.xml文件内容：

<?xml version="1.0" encoding="UTF-8" ?><!--/* * $Id: struts-default.xml 1485719 2013-05-23 14:12:24Z lukaszlenart $ * * 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. */--><!DOCTYPE struts PUBLIC    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"    "http://struts.apache.org/dtds/struts-2.3.dtd"><struts>    <bean class="com.opensymphony.xwork2.ObjectFactory" name="xwork" />    <bean type="com.opensymphony.xwork2.ObjectFactory" name="struts" class="org.apache.struts2.impl.StrutsObjectFactory" />    <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="xwork" 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="xwork" class="com.opensymphony.xwork2.DefaultActionProxyFactory"/>    <bean type="com.opensymphony.xwork2.ActionProxyFactory" name="struts" class="org.apache.struts2.impl.StrutsActionProxyFactory"/>    <bean type="com.opensymphony.xwork2.conversion.ObjectTypeDeterminer" name="tiger" class="com.opensymphony.xwork2.conversion.impl.DefaultObjectTypeDeterminer"/>    <bean type="com.opensymphony.xwork2.conversion.ObjectTypeDeterminer" name="notiger" class="com.opensymphony.xwork2.conversion.impl.DefaultObjectTypeDeterminer"/>    <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.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="struts" class="org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest" scope="default"/>    <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="jakarta" class="org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest" scope="default" />    <constant name="struts.multipart.parser" value="jakarta" />    <bean type="org.apache.struts2.views.TagLibrary" name="s" class="org.apache.struts2.views.DefaultTagLibrary" />    <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" />    <!--  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" />    <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-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="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" />            <!-- 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="multiselect"/>                <interceptor-ref name="actionMappingParams"/>                <interceptor-ref name="params">                    <param name="excludeParams">dojo\..*,^struts\..*,^session\..*,^request\..*,^application\..*,^servlet(Request|Response)\..*,parameters\...*</param>                </interceptor-ref>                <interceptor-ref name="conversionError"/>            </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="multiselect"/>                <interceptor-ref name="params">                    <param name="excludeParams">dojo\..*,^struts\..*,^session\..*,^request\..*,^application\..*,^servlet(Request|Response)\..*,parameters\...*</param>                </interceptor-ref>                <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">                    <param name="excludeParams">dojo\..*,^struts\..*,^session\..*,^request\..*,^application\..*,^servlet(Request|Response)\..*,parameters\...*</param>                </interceptor-ref>                <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="multiselect"/>                <interceptor-ref name="staticParams"/>                <interceptor-ref name="actionMappingParams"/>                <interceptor-ref name="params">                    <param name="excludeParams">dojo\..*,^struts\..*,^session\..*,^request\..*,^application\..*,^servlet(Request|Response)\..*,parameters\...*</param>                </interceptor-ref>                <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-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>

测试代码

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>  <!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.action.extension" value="do,,action"/>      <!--         struts-default包：            1.位置：                struts2-core.jar ==》 struts-default.xml ==》<package name="struts-default" abstract="true">    -->    <package name="default" extends="struts-default">        <!--              ActionSupport类：                1.在action节点中，如果不写class的值的话，默认就是：com.opensymphony.xwork2.ActionSupport                2.原因：因为我们继承了struts-default包，其中有这么一句：                    <default-class-ref class="com.opensymphony.xwork2.ActionSupport" />                3.action节点中默认的method值是execute，result中默认的name是success，在ActionSupport类中有这个方法，                    所以可以不写action节点的class、method和result节点的name属性：                        public String execute() throws Exception {                                return SUCCESS; //public static final String SUCCESS = "success";                            }        -->        <action name="access">            <result  type="redirect">index.jsp</result>        </action>    </package></struts>  

TestActionSupport.java

package top.itcourse.action.support;import java.io.Serializable;import com.opensymphony.xwork2.Action;import com.opensymphony.xwork2.ActionSupport;import com.opensymphony.xwork2.LocaleProvider;import com.opensymphony.xwork2.TextProvider;import com.opensymphony.xwork2.Validateable;import com.opensymphony.xwork2.ValidationAware;/* * ActionSupport *  1.实现的接口： *      public class ActionSupport implements Action, Validateable, ValidationAware,  *          TextProvider, LocaleProvider, Serializable *  2.关于Action接口： *      属性：SUCCESS、NONE、ERROR、INPUT、LOGIN *      方法： execute()  *      说明：我们直接继承ActionSupport,可以直接使用Action类中的属性和方法 *  3.关于Validateable接口（后面学习）： *      方法：valodate *      说明：需要对字段进行验证的时候可以使用 *  4.关于ValidationAware接口（后面学习）： *      属性：包括字段级别的错误消息属性和Action级别的错误消息的属性 *      方法：包括字段级别的错误消息属性和Action级别的错误消息的方法 *      说明：接受和显示错误消息的时候可以使用 *  5.关于TextProvider接口（后面学习）、LocaleProvider接口（后面学习）： *      说明：后面做国际化的时候使用 *  * 继承ActionSupport的好处： *  可以不单独的去实现上面的那些接口，直接继承就行。     */// 2.我们直接继承ActionSupport,可以直接使用Action类中的属性和方法public class TestActionSupport extends ActionSupport {    // 2.我们直接继承ActionSupport,可以直接使用Action类中的属性和方法    // 重写Action类中的execute方法    @Override    public String execute() throws Exception {        // 使用Action类中的SUCCESS属性        return SUCCESS;    }}

其它

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