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apache-spark - StreamingQueryException：文本数据源仅支持单列

问题描述

我知道这个问题之前已经被问过很多次了，但没有一个答案对我有帮助。

下面是我的火花代码

class ParseLogs extends java.io.Serializable {    
def formLogLine(logLine: String): (String,String,String,Int,String,String,String,Int,Float,String,String,Flo at,Int,String,Int,Float,String)={

//some logic

//return value
(recordKey._2.toString().replace("\"", ""),recordKey._3,recordKey._4,recordKey._5,recordKey._6,recordKey._8,sbcId,recordKey._10,recordKey._11,recordKey._12,recordKey._13.trim(),LogTransferTime,contentAccessed,OTT,dataTypeId,recordKey._14,logCaptureTime1)

}
}


 val inputDf = spark.readStream
  .format("kafka")
  .option("kafka.bootstrap.servers", brokers)
  .option("subscribe", topic)
  .option("startingOffsets", "earliest")
  .load()
  val myDf = inputDf.selectExpr("CAST(value AS STRING)")

  val df1 = myDf.map(line =>  new ParseLogs().formLogLine(line.get(0).toString()))

我得到以下错误

User class threw exception: org.apache.spark.sql.streaming.StreamingQueryException: Text data source supports only a single column, and you have 17 columns.;

标签： apache-sparkspark-structured-streaming

解决方案

使用 UDF 将 logLine 转换为您想要的。例如：

    spark.sqlContext.udf.register("YOURLOGIC", (logLine: String) => {
    //some logic
    (recordKey._2.toString().replace("\"",""),recordKey._3,recordKey._4,recordKey._5,recordKey._6,recordKey._8,sbcId,recordKey._10,recordKey._11,recordKey._12,recordKey._13.trim(),LogTransferTime,contentAccessed,OTT,dataTypeId,recordKey._14,logCaptureTime1)
    })
    val inputDf = spark.readStream
      .format("kafka")
      .option("kafka.bootstrap.servers", brokers)
      .option("subscribe", topic)
      .option("startingOffsets", "earliest")
      .load()
    val myDf = inputDf.selectExpr("CAST(value AS STRING)")
    val df1 = myDf.selectExpr("YOURLOGIC(value) as result")
    val result = df1.select(
    df1("result").getItem(0),
    df1("result").getItem(1),
    df1("result").getItem(2)),
    df1("result").getItem(3)),
    ...if you have 17 item,then add to 17
    df1("result").getItem(17))

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