<web-app version="3.1"

         xmlns="http://xmlns.jcp.org/xml/ns/javaee"

         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">

    <context-param>

        <param-name>javax.faces.PROJECT_STAGE</param-name>

        <param-value>Development</param-value>  //该元素用来声明应用范围(整个WEB项目)内的上下文初始化参数。param-name 设定上下文的参数名称。必须是唯一名称。param-value 设定的参数名称的值

    </context-param>

    <servlet>

        <servlet-name>Faces Servlet</servlet-name>

        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>  //<servlet-name> 这个是我们要注册servlet的名字,一般跟Servlet类名有关
<servlet-class> 这个就是指向我们要注册的servlet 的类地址, 要带包路径以上两个包在一个servlet 节点之下.

        <load-on-startup>1</load-on-startup>

    </servlet>

    <servlet-mapping>   //是用来配置我们注册的组件的访问路径,里面包括两个节点

        <servlet-name>Faces Servlet</servlet-name>

        <url-pattern>*.xhtml</url-pattern>

    </servlet-mapping>

    <session-config>

        <session-timeout>  //设置时间

            30

        </session-timeout>

    </session-config>

    <welcome-file-list>  //制定首页

        <welcome-file>index.xhtml</welcome-file>

    </welcome-file-list>

</web-app>