1、struts-default.xml
该文件是Struts2框架的基本配置文件，由框架自动加载。
作用：配置了bean，interceptor，result等
位置：org/apache/struts2/struts-default.xml
这个文件我们需要关注一个地方
这里定义了我们在Struts中使用的默认包 struts-default
这个包中可以看到所有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（拦截器）
<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" />
文件最下边还有两句值得注意
<!--上边其实还定义了许多拦截器栈（interceptorStack）这里在指定默认的拦截栈-->
<default-interceptor-ref name="defaultStack"/>
<!--这里定义了默认请求处理类-->
<default-class-ref class="com.opensymphony.xwork2.ActionSupport" />
<!--也就是说，如果我们没有配置action类，Struts默认会调用这个类去处理。
这个类也就是我们平时继承的ActionSupport，其中也有一个execute，return SUCCESS。
-->
2、default.properties
这个文件中定义了所有框架中的常量
列出几个常用的
struts.i18n.encoding=UTF-8
//上传文件的大小
struts.multipart.maxSize=2097152
//访问的后缀，两个逗号是因为有一个为空，所以我们平时访问才没有加.action后缀
struts.action.extension=action,,
struts.url.http.port = 80
struts.url.https.port = 443
//OGNL中的静态方法访问
struts.ognl.allowStaticMethodAccess=false
修改常量
当然不能直接在文件中改啦~~
1、在struts.xml中
<!-- 配置常量 -->
<constant name="struts.action.extension" value="go"></constant>
2、自定义的struts.properties
文件中可以直接常量名=值，来修改
struts.action.extension=do
3、web.xml中设置
<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、文件加载的优先级
在开发中，后加载文件中的配置会将先加载文件中的配置覆盖。
3、struts-plugin.xml
（先挖一个坑，后面补上）