201671010132 2017-2018第11周Java学习总结

try {
  in = new Scanner(Paths.get("H:\\data1.txt"));
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
         while (in.hasNext())
         {
            String word = in.next();
            long callTime = System.currentTimeMillis();
            words.add(word);
            callTime = System.currentTimeMillis() - callTime;
            totalTime += callTime;
         }
     

      Iterator<String> iter = words.iterator();
      for (int i = 1; i <= 20 && iter.hasNext(); i++)
         System.out.println(iter.next());

这段程序是什么意思？它的作用是什么呢