出现错误:The requested resource (/test/login_confirm) is not available.
xml文件为:<web-app>
<servlet>
<servlet-name>login_confirm</servlet-name>
<servlet-class>login_confirm</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>login_confirm</servlet-name>
<url-pattern>/login_confirm</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>StudentSvlt</servlet-name>
<servlet-class>StudentSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/StudentSvlt</url-pattern>
<servlet-name>StudentSvlt</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>TeacherSvlt</servlet-name>
<servlet-class>TeacherSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/TeacherSvlt</url-pattern>
<servlet-name>TeacherSvlt</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>CourseSvlt</servlet-name>
<servlet-class>CourseSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/CourseSvlt</url-pattern>
<servlet-name>CourseSvlt</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>ClassSvlt</servlet-name>
<servlet-class>ClassSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/ClassSvlt</url-pattern>
<servlet-name>ClassSvlt</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>StudentLoginSvlt</servlet-name>
<servlet-class>StudentLoginSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/StudentLoginSvlt</url-pattern>
<servlet-name>StudentLoginSvlt</servlet-name>
</servlet-mapping>
<servlet>
<servlet-name>MarkSvlt</servlet-name>
<servlet-class>MarkSvlt</servlet-class>
</servlet>
<servlet-mapping>
<url-pattern>/MarkSvlt</url-pattern>
<servlet-name>MarkSvlt</servlet-name>
</servlet-mapping>
</web-app>
在jsp中的程序为:<form name="frmLogin" method="post" action="http://localhost:8080/test/login_confirm" onSubmit="return isValid(this);">
请各位高手帮帮我!谢谢!