发送消息时

Question

我正在使用Websocket在 Spring Boot 2.0.8 中设置聊天应用程序。当我尝试使用网络套接字进行通信时，session.send()抛出异常

java.lang.IllegalStateException: The WebSocket session [1] has been closed and no method (apart from close()) may be called on a closed session
    at org.apache.tomcat.websocket.WsSession.checkState(WsSession.java:806)
    at org.apache.tomcat.websocket.WsSession.getBasicRemote(WsSession.java:432)
    at org.springframework.web.socket.adapter.standard.StandardWebSocketSession.sendTextMessage(StandardWebSocketSession.java:213)
    at org.springframework.web.socket.adapter.AbstractWebSocketSession.sendMessage(AbstractWebSocketSession.java:105)
    at com.example.chat.spring.websocket.WebSocketHandler.handleTextMessage(WebSocketHandler.java:66)
    at org.springframework.web.socket.handler.AbstractWebSocketHandler.handleMessage(AbstractWebSocketHandler.java:43)
    at org.springframework.web.socket.handler.WebSocketHandlerDecorator.handleMessage(WebSocketHandlerDecorator.java:75)
    at org.springframework.web.socket.handler.LoggingWebSocketHandlerDecorator.handleMessage(LoggingWebSocketHandlerDecorator.java:56)
    at org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator.handleMessage(ExceptionWebSocketHandlerDecorator.java:58)
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.handleTextMessage(StandardWebSocketHandlerAdapter.java:113)
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.access$000(StandardWebSocketHandlerAdapter.java:42)
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:84)
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:81)
    at org.apache.tomcat.websocket.WsFrameBase.sendMessageText(WsFrameBase.java:394)
    at org.apache.tomcat.websocket.server.WsFrameServer.sendMessageText(WsFrameServer.java:119)
    at org.apache.tomcat.websocket.WsFrameBase.processDataText(WsFrameBase.java:495)
    at org.apache.tomcat.websocket.WsFrameBase.processData(WsFrameBase.java:294)
    at org.apache.tomcat.websocket.WsFrameBase.processInputBuffer(WsFrameBase.java:133)
    at org.apache.tomcat.websocket.server.WsFrameServer.onDataAvailable(WsFrameServer.java:82)
    at org.apache.tomcat.websocket.server.WsFrameServer.doOnDataAvailable(WsFrameServer.java:171)
    at org.apache.tomcat.websocket.server.WsFrameServer.notifyDataAvailable(WsFrameServer.java:151)
    at org.apache.tomcat.websocket.server.WsHttpUpgradeHandler.upgradeDispatch(WsHttpUpgradeHandler.java:148)
    at org.apache.coyote.http11.upgrade.UpgradeProcessorInternal.dispatch(UpgradeProcessorInternal.java:54)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:53)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)