Record has Long.MIN_VALUE timestamp (= no timestamp marker). Is the time characteristic set to 'ProcessingTime', or did you forget to call 'DataStream.assignTimestampsAndWatermarks(...)

import org.apache.flink.streaming.api.TimeCharacteristic
env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)
 
val inputStream = env.socketTextStream("localhost", 7777)
// 1.先转换成样例数据
val dataStream: DataStream[SensorReading] = inputStream
  .map(
    data => {
      val arr = data.split(",")
      SensorReading(arr(0), arr(1).toLong, arr(2).toDouble)
    }
  )
  .assignTimestampsAndWatermarks(
    WatermarkStrategy.forBoundedOutOfOrderness(Duration.ofSeconds(3))
     .withTimestampAssigner(new SerializableTimestampAssignerTest)
  )