Is your webpage on the same machine as tomcat? The camera on the server tomcat will not be automatically seen by the client machine, and it is impossible for the client machine to see the camera of the server machine remotely.

To use it in a web page, you need to write it in a applet and add a signature to the jar, so that the signed applet can operate the printer, camera, disk and the like on the user's machine at the browser end, otherwise the JVM sandbox will intercept all attempts.