我想從流數據中計算數據，然后發送到網頁。例如：我將計算流數據中 TotalSales 列的總和。但它出錯了summary = dataStream.select('TotalSales').groupby().sum().toPandas()，這是我的代碼。import osfrom pyspark.sql import SparkSessionfrom pyspark.sql.types import StructTypefrom pyspark.sql.functions import *spark = SparkSession.builder.appName("Python Spark SQL basic example").config("spark.some.config.option", "some-value").getOrCreate()schema = StructType().add("_c0", "integer").add("InvoiceNo", "string").add("Quantity","integer").add("InvoiceDate","date").add("UnitPrice","integer").add("CustomerID","double").add("TotalSales","integer")INPUT_DIRECTORY = "C:/Users/HP/Desktop/test/jsonFile"dataStream = spark.readStream.format("json").schema(schema).load(INPUT_DIRECTORY)query = dataStream.writeStream.format("console").start()summary = dataStream.select('TotalSales').groupby().sum().toPandas()print(query.id)query.awaitTermination();這是命令行上顯示的錯誤。Traceback (most recent call last):  File "testStreaming.py", line 12, in <module>    dataStream = dataStream.toPandas()  File "C:\Users\HP\AppData\Local\Programs\Python\Python36\lib\site-packages\pyspark\sql\dataframe.py", line 2150, in toPandas    pdf = pd.DataFrame.from_records(self.collect(), columns=self.columns)  File "C:\Users\HP\AppData\Local\Programs\Python\Python36\lib\site-packages\pyspark\sql\dataframe.py", line 534, in collect    sock_info = self._jdf.collectToPython()  File "C:\Users\HP\AppData\Local\Programs\Python\Python36\lib\site-packages\py4j\java_gateway.py", line 1257, in __call__answer, self.gateway_client, self.target_id, self.name)  File "C:\Users\HP\AppData\Local\Programs\Python\Python36\lib\site-packages\pyspark\sql\utils.py", line 69, in decoraise AnalysisException(s.split(': ', 1)[1], stackTrace)pyspark.sql.utils.AnalysisException: 'Queries with streaming sources must be executed with writeStream.start();;\nFileSource[C:/Users/HP/Desktop/test/jsonFile]'感謝您的回答。