删除无用判断

agri-framework/src/main/java/com/agri/framework/interceptor/MqttMessageHandler.java

@@ -372,7 +372,7 @@ public class MqttMessageHandler implements SmartLifecycle {
                 // 新增：只有在线才转发；不在线就清理残留订阅，解决“取消订阅失败兜底”
                 String onlineKey = "online:" + clientId;
                 Boolean online = stringRedisTemplate.hasKey(onlineKey);
-                if (online == null || !online) {
+                if (!online) {
                     // 不在线：从两边索引移除（避免一直给离线前端发）
                     stringRedisTemplate.opsForSet().remove("sub:" + deviceId, clientId);
                     stringRedisTemplate.opsForSet().remove("subc:" + clientId, deviceId);