servlet 的class文件保存在webapps\servlets-examples\web-inf\class\ 下吧?
<servlet>
        <servlet-name>RequestParamExample</servlet-name>
        <servlet-class>RequestParamExample_dif</servlet-class>
    </servlet><servlet-mapping>
        <servlet-name>RequestParamExample_dif</servlet-name>
        <url-pattern>/servlet/RequestParamExample</url-pattern>(class存放的位置)
    </servlet-mapping>
好像是这样,你在看看吧