用scala写一个wordcount程序

1. 在终端目录/Users/liujingmao/Downloads创建一个文件scala_wordcount，文件包含以下words

 hello word hello word you and me
 you and me hello word cat dog cat
 dog and me you and his miss

2. 在idea中创建一个scala_project,并创建一个WordCountApp的object

   import scala.io.Source
   object WordCountApp {
   def main(args: Array[String]): Unit = {
   
   //the path of the file
   
   val filepath = "/Users/liujingmao/Downloads/scala_wordcount"
   
   /**
     * hello word hello word you and me
     * you and me hello word cat dog cat
     * dog and me you and his miss
     */
   
   // set utf-8
   
   val codec="utf-8"
   
   // read the file from specific file path with passing two parameters(filepath,codec)
   
   val file=Source.fromFile(filepath,codec)
   
   // get the line
   
   val line=file.getLines()
     //.foreach(println)的结果如下所示：
   
   /**
     * hello word hello word you and me
     * you and me hello word cat dog cat
     * dog and me you and his miss
     */
   
     .flatMap(_.split(" ")).toList
   
     //.foreach(println)的结果如下所示：
     /**
       * hello
       * word
       * hello
       * word
       * ......
       */
   
     .map((_,1))
   
     //.foreach(println)的结果如下所示
   
     /**
       * (hello,1)
       * (word,1)
       * (hello,1)
       * (word,1)
       * .......
       */
   
       .groupBy(_._1)
   
     //.foreach(println)的结果如下所示
   
   /**
     * (his,List((his,1)))
     * (dog,List((dog,1), (dog,1)))
     * (miss,List((miss,1)))
     * (you,List((you,1), (you,1), (you,1)))
     * .......
     */
   
   .mapValues(_.size).foreach(println)
   
   //.foreach(println)的结果如下所示：
   
   /**
     * (his,1)
     * (dog,2)
     * (miss,1)
     * (you,3)
     * (me,3)
     * (hello,3)
     * (cat,2)
     * (word,3)
     * (and,4)
     */
     //close the file 
     file.close( )
   }
   }