web.xml

在Tomcat/conf下有一个web.xml文件，当Tomcat中所有web应用实例化时都会读取该配置文件，然后读取每个web应用自己的配置文件（/WEB-INF/web.xml）。

conf/web.xml作出以下配置：

//处理未映射到其他servlet的请求    <servlet>        <servlet-name>default</servlet-name>        <servlet-class>org.apache.catalina.servlets.DefaultServlet</servlet-class>        <init-param>            <param-name>debug</param-name>            <param-value>0</param-value>        </init-param>        <init-param>            <param-name>listings</param-name>            <param-value>false</param-value>        </init-param>        <load-on-startup>1</load-on-startup>    </servlet>//jsp页面编译和执行servlet    <servlet>        <servlet-name>jsp</servlet-name>        <servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>        <init-param>            <param-name>fork</param-name>            <param-value>false</param-value>        </init-param>        <init-param>            <param-name>xpoweredBy</param-name>            <param-value>false</param-value>        </init-param>        <load-on-startup>3</load-on-startup>    </servlet>//映射关系    <!-- The mapping for the default servlet -->    <servlet-mapping>        <servlet-name>default</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping>    <!-- The mappings for the JSP servlet -->    <servlet-mapping>        <servlet-name>jsp</servlet-name>        <url-pattern>*.jsp</url-pattern>        <url-pattern>*.jspx</url-pattern>    </servlet-mapping>//会话设置    <session-config>        <session-timeout>30</session-timeout>    </session-config>//MIME类型映射    <mime-mapping>        <extension>123</extension>        <mime-type>application/vnd.lotus-1-2-3</mime-type>    </mime-mapping>    <mime-mapping>        <extension>3dml</extension>        <mime-type>text/vnd.in3d.3dml</mime-type>    </mime-mapping>    <mime-mapping>        <extension>3ds</extension>        <mime-type>image/x-3ds</mime-type>    </mime-mapping>    <mime-mapping>        <extension>3g2</extension>        <mime-type>video/3gpp2</mime-type>    </mime-mapping>.........