spark streaming not able to use spark sql

问题:

I am facing an issue during spark streaming. I am getting empty records after it gets streamed and passes to the "parse" method.

My code:

import spark.implicits._
import org.apache.spark.sql.types._
import org.apache.spark.sql.Encoders
import org.apache.spark.streaming._
import org.apache.spark.sql.functions._
import org.apache.spark.sql.SparkSession
import spark.implicits._
import org.apache.spark.sql.types.{StructType, StructField, StringType, 
IntegerType}
import org.apache.spark.sql.functions._
import org.apache.spark.sql.SparkSession
import spark.implicits._
import org.apache.spark.sql.types.{StructType, StructField, StringType, 
IntegerType}
import org.apache.spark.SparkConf
import org.apache.spark.streaming.{Seconds, StreamingContext}
import org.apache.spark.storage.StorageLevel
import java.util.regex.Pattern
import java.util.regex.Matcher
import org.apache.spark.sql.hive.HiveContext;
import org.apache.spark.sql.streaming.Trigger
import org.apache.spark.sql._

val conf = new SparkConf().setAppName("streamHive").setMaster("local[*]").set("spark.driver.allowMultipleContexts", "true")

val ssc = new StreamingContext(conf, Seconds(5))    

val sc=ssc.sparkContext

val lines = ssc.textFileStream("file:///home/sadr/testHive")

case class Prices(name: String, age: String,sex: String, location: String)
val sqlContext = new org.apache.spark.sql.SQLContext(sc)

def parse (rdd : org.apache.spark.rdd.RDD[String] ) = 
{
var l = rdd.map(_.split(","))
val prices = l.map(p => Prices(p(0),p(1),p(2),p(3)))
val pricesDf = sqlContext.createDataFrame(prices)
pricesDf.registerTempTable("prices")
pricesDf.show()
var x = sqlContext.sql("select count(*) from prices")
x.show()}
lines.foreachRDD { rdd => parse(rdd)} 
lines.print()
ssc.start()

My input file:

cat test1.csv

Riaz,32,M,uk
tony,23,M,india
manu,33,M,china
imart,34,F,AUS

I am getting this output:

lines.foreachRDD { rdd => parse(rdd)}

lines.print()

ssc.start()

scala> +----+---+---+--------+
|name|age|sex|location|
+----+---+---+--------+
+----+---+---+--------+

I am using Spark version 2.3....I AM GETTING FOLLOWING ERROR AFTER ADDING X.SHOW()

回答1:

Not sure if you are actually able to read the streams.

textFileStream reads only the new files added to the directory after the program starts and not the existing ones. Was the file already there? If yes, remove it from the directory, start the program and copy the file again?