测试数据：
**
* 使用DataFrame实现WordCount
*/
object DataFrameWordCount {
def main(args: Array[String]): Unit = { val spark = SparkSession.builder().appName(this.getClass.getSimpleName).master("local").getOrCreate()
import spark.implicits._
val linesDF = spark.sparkContext.textFile("D:\\workspace\\test_data.txt").toDF("line")
linesDF.show(false)
linesDF.printSchema()
//将一行数据展开
val wordsDF = linesDF.explode("line", "word")((line: String) => line.split(" "))
wordsDF.printSchema()
wordsDF.show(,false)
//对 "word"列进行聚合逻辑并使用count算子计算每个分组元素的个数
val wordCoungDF = wordsDF.groupBy("word").count()
wordCoungDF.show(false)
wordCoungDF.printSchema()
println(wordCoungDF.count() + "----------")
} }
打印结果：
+------------+
|line |
+------------+
| |
| |
| |
| |
+------------+ root
|-- line: string (nullable = true) root
|-- line: string (nullable = true)
|-- word: string (nullable = true) +------------+----+
|line |word|
+------------+----+
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+------------+----+ +----+-----+
|word|count|
+----+-----+
| | |
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+----+-----+ root
|-- word: string (nullable = true)
|-- count: long (nullable = false)