src/main/java/com/dji/sample/component/websocket/service/impl/SendMessageServiceImpl.java
@@ -62,12 +62,14 @@ TextMessage data = new TextMessage(mapper.writeValueAsBytes(message)); for (ConcurrentWebSocketSession session : sessions) { if (!session.isOpen()) { session.close(); log.debug("This session is closed."); return; if (!Objects.isNull(session)) { if (!session.isOpen()) { session.close(); log.debug("This session is closed."); return; } session.sendMessage(data); } session.sendMessage(data); } } catch (IOException e) {