tomcat 9.0 執行 import java.io.IOException; import java.util.ArrayList; import javax.websocket.EncodeException; import javax.websocket.OnClose; import javax.websocket.OnMessage; import javax.websocket.OnOpen; import javax.websocket.Session; import javax.websocket.server.ServerEndpoint; @ServerEndpoint("/websocket") public class WebSocketEndpointTest { //用來存放WebSocket已連接的Socket static ArrayList<Session> sessions; @OnMessage public void onMessage(String message, Session session) throws IOException, InterruptedException, EncodeException { System.out.println("User input: " + message); //session.getBasicRemote().sendText("Hello world Mr. " + message); //for (Session s : session.getOpenSessions()) { for (Session s : sessions) { //對每個連接的Client傳送訊息 ...