url: I requested in the browser

http://localhost:8080

A servlet and < welcome-file-list > are configured in web.xml, respectively, with the following code

<welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<servlet>
    <servlet-name>userservlet</servlet-name>
    <servlet-class>com.tuobida.servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>userservlet</servlet-name>
    <url-pattern>*.html</url-pattern>
</servlet-mapping>

I have defined the servlet, of * .html path matching but also defined the welcome interface (the index.html file does not exist). Why not execute servlet, but report 404