Caused by: org.eclipse.jetty.websocket.api.UpgradeException: 400 Bad Request
at org.eclipse.jetty.websocket.client.WebSocketUpgradeRequest.onComplete用于访问websocket的websocket客户端还基于javax.websocket (即javax.websocket实例.)--其中websocket容器实际上
WebSocket connection to 'ws://www.mydomain.com/socket.io/1/websocket/KUv5G...' failed: Error during WebSockethandshake: 'Connection' header value is not 'Upgrade': keep-alive socket.io.js:2371
那么,如何启用websocket