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任何MVC框架都需要與Web應用整合，這就不得不借助于web.xml文件，只有配置在web.xml文件中Servlet才會被應用加載。?
通常，所有的MVC框架都需要Web應用加載一個核心控制器，對于Struts2框架而言，需要加載FilterDispatcher，只要Web應用負責加載FilterDispatcher，FilterDispatcher將會加載Struts2框架。?
因為Struts2將核心控制器設計成Filter，而不是一個普通Servlet。故為了讓Web應用加載FilterDispatcher，只需要在web.xml文件中配置FilterDispatcher即可。?
標準配置文件如下：

<?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>Struts Blank</display-name> <filter> <!-- 配置Struts2核心Filter的名字 --> <filter-name>struts2</filter-name> <!-- 配置Struts2核心Filter的實現(xiàn)類 --> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> <init-param> <!-- 配置Struts2框架默認加載的Action包結構，可以沒有。 --> <param-name>actionPackages</param-name> <param-value>org.apache.struts2.showcase.person</param-value> </init-param> <!-- 配置Struts2框架的配置提供者類 --> <init-param> <param-name>configProviders</param-name> <param-value>lee.MyConfigurationProvider</param-value> </init-param> </filter> <!-- 配置Filter攔截的URL --> <filter-mapping> <!-- 配置Struts2的核心FilterDispatcher攔截所有用戶請求 --> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> </web-app>

全部配置如下

<?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_9" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"><display-name>Struts Showcase Application</display-name><filter><filter-name>struts-prepare</filter-name><filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareFilter</filter-class></filter><filter><filter-name>struts-execute</filter-name><filter-class>org.apache.struts2.dispatcher.filter.StrutsExecuteFilter</filter-class></filter><filter><filter-name>sitemesh</filter-name><filter-class>com.opensymphony.sitemesh.webapp.SiteMeshFilter</filter-class></filter><filter-mapping><filter-name>struts-prepare</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>sitemesh</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>struts-execute</filter-name><url-pattern>/*</url-pattern></filter-mapping><listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener><listener><listener-class>org.apache.struts2.tiles.StrutsTilesListener</listener-class></listener><!-- Chat Example in Showcase --><listener><listener-class>org.apache.struts2.showcase.chat.ChatSessionListener</listener-class></listener><listener><listener-class>org.apache.struts2.dispatcher.listener.StrutsListener</listener-class></listener><!-- SNIPPET START: dwr --><servlet><servlet-name>dwr</servlet-name><servlet-class>uk.ltd.getahead.dwr.DWRServlet</servlet-class><init-param><param-name>debug</param-name><param-value>true</param-value></init-param></servlet><servlet><servlet-name>JspSupportServlet</servlet-name><servlet-class>org.apache.struts2.views.JspSupportServlet</servlet-class><load-on-startup>1</load-on-startup></servlet><!-- Sitemesh Freemarker and Velocity Decorator Servlets. Shares configuration with Struts.--><servlet><servlet-name>sitemesh-freemarker</servlet-name><servlet-class>org.apache.struts2.sitemesh.FreemarkerDecoratorServlet</servlet-class><init-param><param-name>default_encoding</param-name><param-value>UTF-8</param-value></init-param><load-on-startup>1</load-on-startup></servlet><servlet><servlet-name>sitemesh-velocity</servlet-name><servlet-class>org.apache.struts2.sitemesh.VelocityDecoratorServlet</servlet-class><init-param><param-name>default_encoding</param-name><param-value>UTF-8</param-value></init-param><load-on-startup>1</load-on-startup></servlet><servlet-mapping><servlet-name>dwr</servlet-name><url-pattern>/dwr/*</url-pattern></servlet-mapping><servlet-mapping><servlet-name>sitemesh-freemarker</servlet-name><url-pattern>*.ftl</url-pattern></servlet-mapping><servlet-mapping><servlet-name>sitemesh-velocity</servlet-name><url-pattern>*.vm</url-pattern></servlet-mapping><!-- END SNIPPET: dwr --><!-- SNIPPET START: example.velocity.filter.chain<filter><filter-name>struts-cleanup</filter-name><filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class></filter><filter><filter-name>sitemesh</filter-name><filter-class>org.apache.struts2.sitemesh.VelocityPageFilter</filter-class></filter><filter><filter-name>struts</filter-name><filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class></filter><filter-mapping><filter-name>struts-cleanup</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>sitemesh</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>struts</filter-name><url-pattern>/*</url-pattern></filter-mapping>END SNIPPET: example.velocity.filter.chain --><!-- SNIPPET START: example.freemarker.filter.chain<filter><filter-name>struts-cleanup</filter-name><filter-class>org.apache.struts2.dispatcher.ActionContextCleanUp</filter-class></filter><filter><filter-name>sitemesh</filter-name><filter-class>org.apache.struts2.sitemesh.FreeMarkerPageFilter</filter-class></filter><filter><filter-name>struts</filter-name><filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class></filter><filter-mapping><filter-name>struts-cleanup</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>sitemesh</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>struts</filter-name><url-pattern>/*</url-pattern></filter-mapping>END SNIPPET: example.freemarker.filter.chain --><welcome-file-list><welcome-file>index.jsp</welcome-file><welcome-file>default.jsp</welcome-file><welcome-file>index.html</welcome-file></welcome-file-list><!-- Restricts access to pure JSP files - access available only via Struts action --><security-constraint><display-name>No direct JSP access</display-name><web-resource-collection><web-resource-name>No-JSP</web-resource-name><url-pattern>*.jsp</url-pattern></web-resource-collection><auth-constraint><role-name>no-users</role-name></auth-constraint></security-constraint><security-role><description>Don't assign users to this role</description><role-name>no-users</role-name></security-role></web-app>

*如上，當配置Struts2的FilterDispatcher類時，可以指定一系列的初始化參數(shù)，為該Filter配置初始化參數(shù)時，其中有3個初始化參數(shù)有特殊意義：?
config：使用逗號隔開的字符串，每個字符串都是一個XML配置文件的位置。Struts框架將自動加載該屬性指定的系列配置文件。
actionPackages：使用逗號隔開的字符串，每個字符串都是一個包空間，Struts2框架將掃描這些包空間下的Action。?
configProviders：配置自己的ConfigurationProvider類。?
還可以在此處配置Struts2常量，每個<init-param>元素配置一個Struts2常量，其中<param-name>子元素指定了常量name，而<param-value>子元素指定了常量value。?

*在web.xml中配置了<Filter>元素，還需要配置該Filter攔截的URL。通常，我們讓該Filter攔截所有的用戶請求。可以能過<filter-mapping>元素配置。

轉載于:https://my.oschina.net/u/3346994/blog/906212

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