websockets不会使用xml映射与tomcat 7一起发布

Question

我正在使用Tomcat Web-Socket服务器。我已成功制作服务器并将其与angularJS Client连接。

现在我正在尝试将类导入到我使用tomcat 7.0.56和web.xml进行servlet映射的原始项目中。

服务器启动正常，但在实例化socket

时出现以下错误

的web.xml

<servlet>
    <servlet-name>FirstWebSocketCMS</servlet-name>
    <servlet-class>com.sss.discovery.FirstWebSocketCMS</servlet-class>
</servlet>

 <servlet-mapping>
    <servlet-name>FirstWebSocketCMS</servlet-name>
    <url-pattern>/FirstWebSocketCMS</url-pattern>
  </servlet-mapping>

服务器端：

12:20:51,167 INFO  [FirstWebSocketCMS] Constructor: FirstWebSocketCMS 
Nov 02, 2015 12:20:51 PM org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet FirstWebSocketCMS as unavailable
Nov 02, 2015 12:20:51 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Allocate exception for servlet FirstWebSocketCMS
java.lang.ClassCastException: com.sss.discovery.FirstWebSocketCMS cannot be cast to javax.servlet.Servlet
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1148)

客户端：

 WebSocket connection to 'ws://localhost:8080/sr/FirstWebSocketCMS' failed: Error during WebSocket handshake: Unexpected response code: 500

如果删除web.xml内容并将以下注释添加到类中，则一切正常：

@ServerEndpoint(value = "/FirstWebSocketCMS")
public class FirstWebSocketCMS {
}