Java – how to use jee7 WebSockets to pass parameters to the @ onopen method,

I have this code

@ServerEndpoint(value = "/websocket")
public class Service {
    private String clientId; 
    @OnOpen
    public void init(Session session) throws IOException {
         //opening a websocket
         // get clientId
         clientId = // Code here to get initialization parameter.
    }

}

How do I open a socket from a client to get initialization parameters?

Solution

Depending on what your initialization parameters mean, you can do this:

@ServerEndpoint(value = "/websocket/{clientId}")
public class Service {
    private volatile String clientId; 
    @OnOpen
    public void init(@PathParam("clientId") String clientId,Session session) throws IOException {
         this.clientId = clientId;
    }
}

You will then use the following URL to access your endpoint: WS: / / host / contextpath / websocket / [ClientID]

If you use query parameters, see session #getquerystring()