拦截器是的我们可以在方法的执行前后定义执行的操作。可以作为一个非常有力的工具在数据验证，属性设置，安全，日志等等方面。
拦截器可以链接起来形成一个拦截器栈。框架会按照拦截器定义的顺序依次调用这些拦截器栈里的拦截器。
有时候还可以定义一个默认的拦截器（栈）.
<default-interceptor-ref name="secureStack"/>
每个action还可以定义自己的拦截器栈
<action name="VelocityCounter" class="org.apache.struts2.example.counter.SimpleCounter"> <result name="success">...</result> <interceptor-ref name="defaultComponentStack"/> </action>
在默认的struts-default.xml中就定义了一些默认的拦截器栈，会在大多数的程序中被调用。但是在很多程序中，我们可能需要的功能不一样，比如文件上传，输入验证，二次提交等等。所以，我们就需要定义一些自己的拦截器。
拦截器的原理
配置拦截器：
<package name="default" extends="struts-default"> <interceptors> <interceptor name="timer" class=".."/> <interceptor name="logger" class=".."/> </interceptors> <action name="login" class="tutorial.Login"> <interceptor-ref name="timer"/> <interceptor-ref name="logger"/> <result name="input">login.jsp</result> <result name="success" type="redirectAction">/secure/home</result> </action> </package>
配置拦截器栈：
<package name="default" extends="struts-default"> <interceptors> <interceptor name="timer" class=".."/> <interceptor name="logger" class=".."/> <interceptor-stack name="myStack"> <interceptor-ref name="timer"/> <interceptor-ref name="logger"/> </interceptor-stack> </interceptors> <action name="login" class="tutuorial.Login"> <interceptor-ref name="myStack"/> <result name="input">login.jsp</result> <result name="success" type="redirectAction">/secure/home</result> </action> </package>
也可以参考默认的struts-default.xml
<?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 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.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.factory.StrutsActionProxyFactory"/> <bean type="com.opensymphony.xwork2.ActionProxyFactory" name="prefix" class="org.apache.struts2.factory.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="prototype"/> <bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="jakarta-stream" class="org.apache.struts2.dispatcher.multipart.JakartaStreamMultiPartRequest" scope="prototype"/> <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="prototype" /> <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.PropertyAccessor" name="org.apache.struts2.dispatcher.HttpParameters" class="com.opensymphony.xwork2.ognl.accessor.HttpParametersPropertyAccessor" /> <bean type="ognl.PropertyAccessor" name="org.apache.struts2.dispatcher.Parameter" class="com.opensymphony.xwork2.ognl.accessor.ParameterPropertyAccessor" /> <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="prototype" /> <bean type="com.opensymphony.xwork2.security.AcceptedPatternsChecker" name="struts" class="com.opensymphony.xwork2.security.DefaultAcceptedPatternsChecker" scope="prototype" /> <bean type="com.opensymphony.xwork2.config.providers.ValueSubstitutor" class="com.opensymphony.xwork2.config.providers.EnvsValueSubstitutor" scope="singleton"/> <package name="struts-default" abstract="true" strict-method-invocation="true"> <result-types> <result-type name="chain" class="com.opensymphony.xwork2.ActionChainResult"/> <result-type name="dispatcher" class="org.apache.struts2.result.ServletDispatcherResult" default="true"/> <result-type name="freemarker" class="org.apache.struts2.views.freemarker.FreemarkerResult"/> <result-type name="httpheader" class="org.apache.struts2.result.HttpHeaderResult"/> <result-type name="redirect" class="org.apache.struts2.result.ServletRedirectResult"/> <result-type name="redirectAction" class="org.apache.struts2.result.ServletActionRedirectResult"/> <result-type name="stream" class="org.apache.struts2.result.StreamResult"/> <result-type name="velocity" class="org.apache.struts2.result.VelocityResult"/> <result-type name="xslt" class="org.apache.struts2.views.xslt.XSLTResult"/> <result-type name="plainText" class="org.apache.struts2.result.PlainTextResult" /> <result-type name="postback" class="org.apache.struts2.result.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="org.apache.struts2.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" /> <!-- 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-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-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" /> <global-allowed-methods>execute,input,back,cancel,browse,save,delete,list,index</global-allowed-methods> </package> </struts>
自定义拦截器
拦截器必须实现 com.opensymphony.xwork2.interceptor.Interceptor 接口。
public interface Interceptor extends Serializable {
void destroy();
void init();
String intercept(ActionInvocation invocation) throws Exception;
}
init()方法在拦截器被实例化后，interceptor()方法之前执行，用来配置拦截器需要用到的资源。
interceptor()方法就是用来写拦截的代码的，就像一个普通的action的方法，拦截器返回一个结果来把请求传给容器的其他资源。调用ActionInvocation来执行这个action或者其他拦截器。
配置方式
<struts> ... <package name="struts-default"> <interceptors> <interceptor name="alias" class="com.opensymphony.xwork2.interceptor.AliasInterceptor"/> <interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/> ... </interceptors> </package> ... </struts>
自定义拦截器实例
import com.opensymphony.xwork2.ActionInvocation; import com.opensymphony.xwork2.interceptor.AbstractInterceptor; public class SimpleInterceptor extends AbstractInterceptor { public String intercept(ActionInvocation invocation) throws Exception { MyAction action = (MyAction)invocation.getAction(); action.setDate(new Date()); return invocation.invoke(); } }