修改Struts2的struts.xml配置文件位置和名称-重点是init-param参数用来切换加载的路径

默认情况下，Struts2的配置文件名称为struts.xml，且该文件放在src根目录下。项目加载时会自动加载该struts.xml，如下图所示：

如果需要修改struts.xml的位置，例如把struts.xml放到struts2文件夹下，结构如下图所示，该怎么办呢？

Struts2在web.xml中的一般配置如下：

 <filter>
     <filter-name>struts2filter-name>
     <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilterfilter-class>
 filter>
 <filter-mapping>
     <filter-name>struts2filter-name>
     <url-pattern>/*url-pattern>
 filter-mapping>

为了弄清Stuts2是如何加载配置文件的，先查看Struts2的StrutsPrepareAndExecuteFilter类：

 package org.apache.struts2.dispatcher.ng.filter;
 /**
  * Handles both the preparation and execution phases of the Struts dispatching process.  This filter is better to use
  * when you don't have another filter that needs access to action context information, such as Sitemesh.
  */
 public class StrutsPrepareAndExecuteFilter implements StrutsStatics, Filter {
     protected PrepareOperations prepare;
     protected ExecuteOperations execute;
     protected List excludedPatterns = null;

     public void init(FilterConfig filterConfig) throws ServletException {
         InitOperations init = new InitOperations();
         try {
             FilterHostConfig config = new FilterHostConfig(filterConfig);
             init.initLogging(config);
             Dispatcher dispatcher = init.initDispatcher(config);
             init.initStaticContentLoader(config, dispatcher);

             prepare = new PrepareOperations(filterConfig.getServletContext(), dispatcher);
             execute = new ExecuteOperations(filterConfig.getServletContext(), dispatcher);
             this.excludedPatterns = init.buildExcludedPatternsList(dispatcher);

             postInit(dispatcher, filterConfig);
         } finally {
             init.cleanup();
         }

     }

     /**
      * Callback for post initialization
      */
     protected void postInit(Dispatcher dispatcher, FilterConfig filterConfig) {
     }

     public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {

         HttpServletRequest request = (HttpServletRequest) req;
         HttpServletResponse response = (HttpServletResponse) res;

         try {
             prepare.setEncodingAndLocale(request, response);
             prepare.createActionContext(request, response);
             prepare.assignDispatcherToThread();
             if ( excludedPatterns != null && prepare.isUrlExcluded(request, excludedPatterns)) {
                 chain.doFilter(request, response);
             } else {
                 request = prepare.wrapRequest(request);
                 ActionMapping mapping = prepare.findActionMapping(request, response, true);
                 if (mapping == null) {
                     boolean handled = execute.executeStaticResourceRequest(request, response);
                     if (!handled) {
                         chain.doFilter(request, response);
                     }
                 } else {
                     execute.executeAction(request, response, mapping);
                 }
             }
         } finally {
             prepare.cleanupRequest(request);
         }
     }

     public void destroy() {
         prepare.cleanupDispatcher();
     }
 }

可以看到，有个public void init(FilterConfig filterConfig) throws ServletException { ... } 方法，很明显，这个方法在启动时会被调用，然后加载classes目录下的struts.xml配置文件。配置文件参数名称为filterConfig。因此，我们可以指定Struts2 Filter 的参数，这和指定Servlet参数相同，配置即可。配置如下：

 <filter>
     <filter-name>struts2filter-name>
     <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilterfilter-class>
     <init-param>
         <param-name>filterConfigparam-name>
         <param-value>classpath:struts2/struts.xmlparam-value>
     init-param>
 filter>
 <filter-mapping>
     <filter-name>struts2filter-name>
     <url-pattern>/*url-pattern>
 filter-mapping>

这样配置后，就可以正常加载指定的Struts配置文件了。