[Java EE] Implement Client with WebSocket

Recently, the Qiita article has become a progress report. This time, it is a continuation of the article here.

Addition of tyrus-standalone-client

When I write and execute a client program normally, I get the following error.

Exception in thread "main" java.lang.RuntimeException: Could not find an implementation class.
	at javax.websocket.ContainerProvider.getWebSocketContainer(ContainerProvider.java:73)
	at Main.main(Main.java:46)

According to stackoverrun, websocket provides a Client interface, but doesn't seem to provide an implementation. Therefore, we will introduce tyrus-standalone-client in glassfish. How to implement WebSocketContainer in StandardWebSocketClient class

Specifically, add it to the dependencies of build.gradle.

dependencies {
    //I explained last time
    compileOnly 'javax:javaee-api:8.0'
    //This is what I will add this time
    compile group: 'org.glassfish.tyrus.bundles', name: 'tyrus-standalone-client', version: '1.14'
}

Write ClientEndPoint

So, let's write a program this time. -> src-> main-> Create a .java file in (appropriate package) in java.

import javax.websocket.*;
import java.net.URI;
import java.util.Scanner;

//With this annotation, it is recognized as the endpoint of the client.
@ClientEndpoint
public class Client {

    public Client() {
        super();
    }

    //Processing when establishing a session
    @OnOpen
    public void onOpen(Session session) {
        System.out.println("[Session establishment]");
    }

    //Processing when receiving a message
    @OnMessage
    public void onMessage(String message) {
        System.out.println("[Receive]:" + message);
    }

    //Processing when receiving a message
    @OnError
    public void onError(Throwable th) {
        System.err.println(th.getMessage());
    }

    //Processing at session release
    @OnClose
    public void onClose(Session session) {
        System.out.println("[Disconnect]");
    }

    static public void main(String[] args) throws Exception {

        //Get the object of WebSocket container for initialization
        WebSocketContainer container = ContainerProvider
                .getWebSocketContainer();
        //Server endpoint URI
        URI uri = URI
                .create("ws://localhost:8080/<Project name>/<Link>");
        //Establish a session with the server endpoint
        //From the running client, look for the same class passed as an argument and connect?
        Session session = container.connectToServer(Client.class, uri);

        while (!session.isOpen()) {
            Thread.sleep(500);
        }

        System.out.println("open");

        try (Scanner s = new Scanner(System.in)) {
            String str;
            System.out.println("start loop");
            while (true) {
                str = s.nextLine();
                if(str.equals("exit")) break;
                //Send the contents of str
                session.getBasicRemote().sendText(str);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

Since it is troublesome, I wrote main in the Endpoint class this time, but I feel that it is better to separate it.

Run

First, start the server containing Client with tomcatRun etc., and then execute main in another window.