scala – Spark:以ORC格式保存Dataframe
发布时间:2020-12-16 18:53:51 所属栏目:安全 来源:网络整理
导读:在之前的版本中,我们曾经在RDD上使用’saveAsOrcFile()’方法.现在已经不见了!如何以ORC文件格式保存DataFrame中的数据? def main(args: Array[String]) {println("Creating Orc File!")val sparkConf = new SparkConf().setAppName("orcfile")val sc = ne
在之前的版本中,我们曾经在RDD上使用’saveAsOrcFile()’方法.现在已经不见了!如何以ORC文件格式保存DataFrame中的数据?
def main(args: Array[String]) { println("Creating Orc File!") val sparkConf = new SparkConf().setAppName("orcfile") val sc = new SparkContext(sparkConf) val hiveContext = new org.apache.spark.sql.hive.HiveContext(sc) val people = sc.textFile("/apps/testdata/people.txt") val schemaString = "name age" val schema = StructType(schemaString.split(" ").map(fieldName => {if(fieldName == "name") StructField(fieldName,StringType,true) else StructField(fieldName,IntegerType,true)})) val rowRDD = people.map(_.split(",")).map(p => Row(p(0),new Integer(p(1).trim))) //# Infer table schema from RDD** val peopleSchemaRDD = hiveContext.createDataFrame(rowRDD,schema) //# Create a table from schema** peopleSchemaRDD.registerTempTable("people") val results = hiveContext.sql("SELECT * FROM people") results.map(t => "Name: " + t.toString).collect().foreach(println) // Now I want to save this Dataframe(peopleSchemaRDD) in ORC Format. How do I do that? } 解决方法
从Spark 1.4开始,您只需使用DataFrameWriter并将格式设置为orc:
peopleSchemaRDD.write.format("orc").save("people") 要么 peopleSchemaRDD.write.orc("people") (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |