18.8 Path Parameters

The ServerEndpoint annotation enables you to use URI templates to specify parts of an endpoint deployment URI as application parameters. For example, consider this endpoint:

@ServerEndpoint("/chatrooms/{room-name}")
public class ChatEndpoint {
   ...
}

If the endpoint is deployed inside a web application called chatapp at a local Java EE server in port 8080, clients can connect to the endpoint using any of the following URIs:

http://localhost:8080/chatapp/chatrooms/currentnews
http://localhost:8080/chatapp/chatrooms/music
http://localhost:8080/chatapp/chatrooms/cars
http://localhost:8080/chatapp/chatrooms/technology

Annotated endpoints can receive path parameters as arguments in methods annotated with @OnOpen, @OnMessage, and @OnClose. In this example, the endpoint uses the parameter in the @OnOpen method to determine which chat room the client wants to join:

@ServerEndpoint("/chatrooms/{room-name}")
public class ChatEndpoint {
   @OnOpen
   public void open(Session session, 
                    EndpointConfig c, 
                    @PathParam("room-name") String roomName) {
      // Add the client to the chat room of their choice ...
   }
}

The path parameters used as arguments in these methods can be strings, primitive types, or the corresponding wrapper types.