使用SparkSQL编写wordCount的词频统计

# 使用SparkSQL编写wordCount的词频统计

## word.txt
```
hello hello scala spark
java sql html java hello
jack jack tom tom you he he sql
```
 
## spark 代码：
```
object WordCount {

def main(args: Array[String]): Unit = {

val spark: SparkSession = SparkSession.builder()
.appName("wordCount")
.master("local[*]")
.getOrCreate()

//读取数据
val ds: Dataset[String] = spark.read.textFile("文件路径")
//引包，不然无法调用 flatMap()
import spark.implicits._
//整理数据 (切分压平)
val ds1: Dataset[String] = ds.flatMap(_.split(" "))
//构建临时表
ds1.createTempView("word")
//执行 SQL 语句，结果倒序
val df: DataFrame = spark.sql("select value,count(*) count from word group by value order by count desc")
//展示
df.show()
//关闭
spark.stop()
}

}
```
 
## 运行结果：
```
+-----+-----+
|value|count|
+-----+-----+
|hello| 3|
| tom| 2|
| java| 2|
| sql| 2|
| he| 2|
| jack| 2|
| you| 1|
| html| 1|
|spark| 1|
|scala| 1|
+-----+-----+
```

 
 
 
*如果哪里有错误，欢迎大家指出...*