A question about websocket API-- Annotation ServerEndpoint

[王琳]

Hi friend:
 i have a question. use Tomcat 8.5.15
@ServerEndpoint API has 'value' summary. This value mapping url.When the url 
has parameter,use {}.
for example:
@ServerEndpoint(value = 
"/websocket/fmsWebsocket/{userId}/{companyId}/{groupId}")

js:var url = "ws://192.168.0.6:8080/note/websocket/fmsWebsocket/1/1/1";

My question is when {userId} is null or {companyId} is null or {groupId} is 
null . How  write @ ServerEndpoint(value=??????).
and
js: var url = "ws://192.168.0.6:8080/note/websocket/fmsWebsocket///1";
is right?

Thank you very much!