本篇文章给大家分享的是有关Struts2的配置文件web.xml是怎样的，小编觉得挺实用的，因此分享给大家学习，希望大家阅读完这篇文章后可以有所收获，话不多说，跟着小编一起来看看吧。
任何MVC框架都需要与Web应用整合，这就不得不借助于web.xml文件，只有配置在web.xml文件中Servlet才会被应用加载。
通常，所有的MVC框架都需要Web应用加载一个核心控制器，对于Struts2框架而言，需要加载FilterDispatcher，只要Web应用负责加载FilterDispatcher，FilterDispatcher将会加载Struts2框架。
因为Struts2将核心控制器设计成Filter，而不是一个普通Servlet。故为了让Web应用加载FilterDispatcher，只需要在web.xml文件中配置FilterDispatcher即可。
标准配置文件如下：
<?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的实现类 --> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> <init-param> <!-- 配置Struts2框架默认加载的Action包结构，可以没有。 --> <param-name>actionPackages</param-name> <param-value>org.apache.struts2.showcase.person</param-value> </init-param> <!-- 配置Struts2框架的配置提供者类 --> <init-param> <param-name>configProviders</param-name> <param-value>lee.MyConfigurationProvider</param-value> </init-param> </filter> <!-- 配置Filter拦截的URL --> <filter-mapping> <!-- 配置Struts2的核心FilterDispatcher拦截所有用户请求 --> <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，当配置Struts2的FilterDispatcher类时，可以指定一系列的初始化参数，为该Filter配置初始化参数时，其中有3个初始化参数有特殊意义：
config：使用逗号隔开的字符串，每个字符串都是一个XML配置文件的位置。Struts框架将自动加载该属性指定的系列配置文件。
actionPackages：使用逗号隔开的字符串，每个字符串都是一个包空间，Struts2框架将扫描这些包空间下的Action。
configProviders：配置自己的ConfigurationProvider类。
还可以在此处配置Struts2常量，每个<init-param>元素配置一个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，还需要配置该Filter拦截的URL。通常，我们让该Filter拦截所有的用户请求。可以能过<filter-mapping>元素配置。
以上就是Struts2的配置文件web.xml是怎样的，小编相信有部分知识点可能是我们日常工作会见到或用到的。希望你能通过这篇文章学到更多知识。更多详情敬请关注亿速云行业资讯频道。
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