Struts2的配置文件web.xml是怎樣的

本篇文章給大家分享的是有關(guān)Struts2的配置文件web.xml是怎樣的，小編覺得挺實用的，因此分享給大家學(xué)習(xí)，希望大家閱讀完這篇文章后可以有所收獲，話不多說，跟著小編一起來看看吧。

任何MVC框架都需要與Web應(yīng)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(yīng)用加載。 
通常，所有的MVC框架都需要Web應(yīng)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(yīng)用負(fù)責(zé)加載FilterDispatcher，F(xiàn)ilterDispatcher將會加載Struts2框架。 
因為Struts2將核心控制器設(shè)計成Filter，而不是一個普通Servlet。故為了讓W(xué)eb應(yīng)用加載FilterDispatcher，只需要在web.xml文件中配置FilterDispatcher即可。 
標(biāo)準(zhǔn)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(rèn)加載的Action包結(jié)構(gòu)，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(dāng)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?？梢阅苓^<filter-mapping>元素配置。

以上就是Struts2的配置文件web.xml是怎樣的，小編相信有部分知識點可能是我們?nèi)粘９ぷ鲿姷交蛴玫降?。希望你能通過這篇文章學(xué)到更多知識。更多詳情敬請關(guān)注億速云行業(yè)資訊頻道。