日志输出，空指针导致程序出错-测试获取帧

handler/tool.go

@@ -187,6 +187,10 @@ func subscribeAndHandleMessagesV3(ws *websocket.Conn, device_id int) {
 					goto end
 				}
 				c = count
+				err4 := img.Close()
+				if err4 != nil {
+					log.Printf("close img err:%v", err)
+				}
 			}
 		} else {
 			//每秒发送一次心跳检测
@@ -201,10 +205,6 @@ func subscribeAndHandleMessagesV3(ws *websocket.Conn, device_id int) {
 		}
 		time.Sleep(100 * time.Millisecond)
 		t_count++
-		err := img.Close()
-		if err != nil {
-			log.Printf("close img err:%v", err)
-		}
 	}
 
 end:

service/tool.go

@@ -50,11 +50,12 @@ func GetDeviceCurrentFrame(deviceId int) (gocv.Mat, int) {
 	//获取读写锁
 	mutex_, ok := DeviceRWMap.Load(deviceId)
 	if !ok {
+		log.Printf("DeviceRWMap 读写锁不存在，device_id: %d \n", deviceId)
 		return gocv.NewMat(), -1
 	}
 	mutex, ok := mutex_.(*sync.RWMutex)
 	if !ok {
-		log.Printf("DeviceRWMap 存储的不是 *sync.RWMutex 类型，device_id: %d", deviceId)
+		log.Printf("DeviceRWMap 存储的不是 *sync.RWMutex 类型，device_id: %d \n", deviceId)
 		return gocv.NewMat(), -1
 	}
 	mutex.RLock()
@@ -66,7 +67,7 @@ func GetDeviceCurrentFrame(deviceId int) (gocv.Mat, int) {
 	}
 	frame, ok := frameIface.(gocv.Mat)
 	if !ok {
-		log.Printf("DeviceCurrentFrameMap 存储的不是 gocv.Mat 类型，device_id: %d", deviceId)
+		log.Printf("DeviceCurrentFrameMap 存储的不是 gocv.Mat 类型，device_id: %d \n", deviceId)
 	}
 	frame_countIface, ok := DeviceFrameCount.Load(deviceId)
 	if !ok {