修改Struts2的struts.xml配置文件位置

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。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：

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<!-- 配置struts2过滤器：StrutsPrepareAndExecuteFilter -->  
<filter>  
    <filter-name>struts2</filter-name>  
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>  
</filter>  
<filter-mapping>  
    <filter-name>struts2</filter-name>  
    <url-pattern>/*</url-pattern>  
</filter-mapping>  

<!-- 配置struts2过滤器：StrutsPrepareAndExecuteFilter -->
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-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：

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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<Pattern> 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();  
    }  
}  

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<Pattern> 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<init-param>即可。配置如下：

[html]
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<filter>  
    <filter-name>struts2</filter-name>  
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>  
    <init-param>  
        <param-name>filterConfig</param-name>  
        <param-value>classpath:struts2/struts.xml</param-value>  
    </init-param>  
</filter>  
<filter-mapping>  
    <filter-name>struts2</filter-name>  
    <url-pattern>/*</url-pattern>  
</filter-mapping>  

<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
<init-param>
<param-name>filterConfig</param-name>
<param-value>classpath:struts2/struts.xml</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>struts2</filter-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。