struts2 默认拦截器解析

使用struts2，拦截器大家经常使用，当然默认情况我们除了自定义的拦截器外，会使用struts2默认的拦截器，那他究竟有哪些默认的拦截器？每个拦截器都是做什么的呢？我们来看下对应的源码，打开对应源码下的struts2-default.xml文件

我们可以看到对应很多的拦截器信息，如下

拦截器信息：

       <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="createSession" class="org.apache.struts2.interceptor.CreateSessionInterceptor" />            <interceptor name="debugging" class="org.apache.struts2.interceptor.debugging.DebuggingInterceptor" />            <interceptor name="externalRef" class="com.opensymphony.xwork2.interceptor.ExternalReferencesInterceptor"/>            <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="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="sessionAutowiring" class="org.apache.struts2.spring.interceptor.SessionContextAutowiringInterceptor"/>            <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" />   <!-- Deprecated name forms scheduled for removal in Struts 2.1.0. The camelCase versions are preferred. See ww-1707 -->            <interceptor name="external-ref" class="com.opensymphony.xwork2.interceptor.ExternalReferencesInterceptor"/>            <interceptor name="model-driven" class="com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor"/>            <interceptor name="static-params" class="com.opensymphony.xwork2.interceptor.StaticParametersInterceptor"/>            <interceptor name="scoped-model-driven" class="com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor"/>            <interceptor name="servlet-config" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>            <interceptor name="token-session" class="org.apache.struts2.interceptor.TokenSessionStoreInterceptor"/>

拦截器栈信息：

<!-- 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="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 params-prepare-params 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="params"/>                <interceptor-ref name="servletConfig"/>                <interceptor-ref name="prepare"/>                <interceptor-ref name="i18n"/>                <interceptor-ref name="chain"/>                <interceptor-ref name="modelDriven"/>                <interceptor-ref name="fileUpload"/>                <interceptor-ref name="checkbox"/>                <interceptor-ref name="staticParams"/>                <interceptor-ref name="params"/>                <interceptor-ref name="conversionError"/>                <interceptor-ref name="validation">                    <param name="excludeMethods">input,back,cancel</param>                </interceptor-ref>                <interceptor-ref name="workflow">                    <param name="excludeMethods">input,back,cancel</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                 servlet-config 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="prepare"/>                <interceptor-ref name="i18n"/>                <interceptor-ref name="chain"/>                <interceptor-ref name="debugging"/>                <interceptor-ref name="profiling"/>                <interceptor-ref name="scopedModelDriven"/>                <interceptor-ref name="modelDriven"/>                <interceptor-ref name="fileUpload"/>                <interceptor-ref name="checkbox"/>                <interceptor-ref name="staticParams"/>                <interceptor-ref name="params">                  <param name="excludeParams">dojo\..*</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>            <!-- 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><default-interceptor-ref name="defaultStack"/>

当然还有很多拦截器栈，我们先来看拦截器

以上就是struts2默认的拦截器，我们大部分时间是不需要单独配置这些拦截器的，一般都是配置对应的拦截器栈，下面我们来看对应的拦截器栈都有哪些？都是做什么的？

已配置栈名

包含的拦截器

描    述

basicStack

exception、servletConfig、prepare、checkbox、params、conversionError

如使用栈，最起码要使用这几个拦截器

validationWorkflowStack

basicStack、validation、workflow

在基本栈的基础上增加验证和工作流特性

fileUploadStack

fileUpload、basicStack

在基本栈的基础上增加文件上传特性

modelDrivenStack

modelDriven、basicStack

在基本栈的基础上增加模型功能特性

chainStack

chain、basicStack

在基本栈的基础上增加链接特性

i18nStack

i18n、basicStack

在基本栈的基础上增加区域持久化特性

paramPrepareParamsStack

exception、alias、params、servletConfig、prepare、i18n、chain、modelDriven、file- Upload、checkbox、staticParams、params、conversionError、vali- dation、workflow

提供包括前action（pre-action）方法调用的完整栈。params栈使用两次：第一次是在调用prepare()方法之前提供参数，第二次是在预备阶段为可能被检索的对象重新使用参数

defaultStack

exception、alias、servlet- Config、prepare、i18n、chain、debugging、profiling、scoped- ModelDriven、modelDriven、fileUpload、checkbox、static- Params、params、conversion- Error、validation、workflow

提供一个完整栈，包括调试和概要

executeAndWaitStack

execAndWait、defaultStack、execAndWait

提供执行与等待栈，比如在上传文件时需要向用户显示一个等待页面时，就可以使用这个栈

如果不配置拦截器，默认使用他自己的defaultStack，我们看到，defaultStack包含了基本上所有的拦截器，所以基本上都能满足我们的需求，但是我们一般情况下用不了这么多拦截器栈的，经过这么多拦截器栈肯定会影响性能的，所以我们可以根据不通的场景，选择合适的拦截器栈。如下面的action只需要上传，那我们只需要添加上次的拦截器即可！