1、struts-default.xml

該檔案是Struts2框架的基本配置檔案，由框架自動載入。
作用：配置了bean，interceptor，result等
位置：org/apache/struts2/struts-default.xml

這個檔案我們需要關注一個地方

這裡定義了我們在Struts中使用的預設包 struts-default
這個包中可以看到所有result-type

<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>

以及interceptor（攔截器）

<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="paramRemover" class="com.opensymphony.xwork2.interceptor.ParameterRemoverInterceptor"/>
<interceptor name="actionMappingParams" class="org.apache.struts2.interceptor.ActionMappingParametersInterceptor"/>
<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="annotationParameterFilter" class="com.opensymphony.xwork2.interceptor.annotations.AnnotationParameterFilterInterceptor" />
<interceptor name="multiselect" class="org.apache.struts2.interceptor.MultiselectInterceptor" />
<interceptor name="noop" class="org.apache.struts2.interceptor.NoOpInterceptor" />

檔案最下邊還有兩句值得注意

<!--上邊其實還定義了許多攔截器棧（interceptorStack）這裡在指定預設的攔截棧-->
<default-interceptor-ref name="defaultStack"/>
<!--這裡定義了預設請求處理類-->
<default-class-ref class="com.opensymphony.xwork2.ActionSupport" />
<!--也就是說，如果我們沒有配置action類，Struts預設會呼叫這個類去處理。
這個類也就是我們平時繼承的ActionSupport，其中也有一個execute，return SUCCESS。
-->

2、default.properties

這個檔案中定義了所有框架中的常量

列出幾個常用的

struts.i18n.encoding=UTF-8
//上傳檔案的大小
struts.multipart.maxSize=2097152
//訪問的字尾，兩個逗號是因為有一個為空，所以我們平時訪問才沒有加.action字尾
struts.action.extension=action,,

struts.url.http.port = 80
struts.url.https.port = 443
//OGNL中的靜態方法訪問
struts.ognl.allowStaticMethodAccess=false

修改常量
當然不能直接在檔案中改啦~~
1、在struts.xml中

<!-- 配置常量 -->  
<constant name="struts.action.extension" value="go"></constant>

2、自定義的struts.properties

檔案中可以直接常量名=值，來修改

struts.action.extension=do

3、web.xml中設定

<filter>
    <filter-name>filter</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    <init-param>
        <param-name>struts.action.extension</param-name>
        <param-value>php</param-value>
    </init-param>
</filter>      
<filter-mapping>
    <filter-name>filter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

4、檔案載入的優先順序
在開發中，後加載檔案中的配置會將先載入檔案中的配置覆蓋。

3、struts-plugin.xml

（先挖一個坑，後面補上）