Reputation: 361
I am executing following code to create a data frame from a text file .
import org.apache.spark.SparkContext
import org.apache.spark.SparkConf
import org.apache.spark.sql.{SQLContext, Row}
import org.apache.spark.sql.types.{StructType, StringType, StructField}
/**
* Created by PSwain on 6/19/2016.
*/
object RddToDataframe extends App {
val scnf=new SparkConf().setAppName("RddToDataFrame").setMaster("local[1]")
val sc = new SparkContext(scnf)
val sqlContext = new SQLContext(sc)
val employeeRdd=sc.textFile("C:\\Users\\pswain\\IdeaProjects\\test1\\src\\main\\resources\\employee")
//Creating schema
val employeeSchemaString="id name age"
val schema = StructType(employeeSchemaString.split(",").map( colNmae => StructField(colNmae,StringType,true)))
//Creating RowRdd
val rowRdd= employeeRdd.map(row => row.split(",")).map(row => Row(row(0).trim.toInt,row(1),row(2).trim.toInt))
//Creating dataframe = RDD[rowRdd] + schema
val employeeDF=sqlContext.createDataFrame(rowRdd,schema). registerTempTable("Employee")
sqlContext.sql("select * from Employee").show()
}
But while executing in InteliJ I am finding type mismatch error as below . Not able to identify why this error is comming I am just converting string to integer . Employee file has below input , they are showing all in one line , but they are one line each .
1201, satish, 25 1202, krishna, 28 1203, amith, 39 1204, javed, 23 1205, prudvi, 23
16/06/19 15:18:58 ERROR Executor: Exception in task 0.0 in stage 0.0 (TID 0)
scala.MatchError: 1201 (of class java.lang.Integer)
at org.apache.spark.sql.catalyst.CatalystTypeConverters$StringConverter$.toCatalystImpl(CatalystTypeConverters.scala:295)
at org.apache.spark.sql.catalyst.CatalystTypeConverters$StringConverter$.toCatalystImpl(CatalystTypeConverters.scala:294)
at org.apache.spark.sql.catalyst.CatalystTypeConverters$CatalystTypeConverter.toCatalyst(CatalystTypeConverters.scala:102)
Upvotes: 2
Views: 6671
Reputation: 847
The schema is created with all the column types are defined as StringType.
val schema = StructType(employeeSchemaString.split(",").map( colNmae => StructField(colNmae,StringType,true)))
But the rowRDD has columns of type int, string and int.
Here is the working code
val structType= {
val id = StructField("id", IntegerType)
val name = StructField("name", StringType)
val age = StructField("age", IntegerType)
new StructType(Array(id, name , age))
}
val rowRdd= employeeRdd.map(row => row.split(",")).map(row => Row(row(0).trim().toInt,row(1),row(2).trim().toInt))
sqlContext.createDataFrame(rowRdd,structType). registerTempTable("Employee")
sqlContext.sql("select * from Employee").show()
Upvotes: 6