如何遍历HashSet并返回带有限定元素的集合？

Question

我想要做的是从包含500,000英文单词的文本文件中读取并将其存储到HashSet以达到性能目的。然后我想返回一个包含合格元素的HashSet，例如5个字母的单词，6个字母的单词等。

这是我的代码，至今我不知道该怎么做。 我很感谢你的解决方案！

private static HashSet<String> readPuzzleFile(int wordLength) { 
     HashSet<String> unProcessedPuzzle = new HashSet<String>(); 
     try (Scanner file = new Scanner(new File(PATHTOPUZZLE))) { 
      while (file.hasNextLine()) { 
       unProcessedPuzzle.add(file.nextLine()); 
      } 
     } catch (FileNotFoundException e) { 
      System.out.println("No Puzzle File Found!"); 
      return null; 
     } 
     HashSet<String> puzzle = new HashSet<String>(); 
     Iterator iterator = unProcessedPuzzle.iterator(); 
     for (String word : unProcessedPuzzle){ 
      puzzle.addAll(word); 
     } 
     } 

Answer 1

private static HashSet<String> readPuzzleFile(int wordLength) { 
     HashSet<String> unProcessedPuzzle = new HashSet<String>(); 
     try (Scanner file = new Scanner(new File(PATHTOPUZZLE))) { 
      while (file.hasNextLine()) { 
       unProcessedPuzzle.add(file.nextLine()); 
      } 
     } catch (FileNotFoundException e) { 
      System.out.println("No Puzzle File Found!"); 
      return null; 
     } 
     HashSet<String> puzzle = new HashSet<String>(); 
     Iterator iterator = unProcessedPuzzle.iterator(); 
     for (String word : unProcessedPuzzle){ 
      puzzle.add(word); //........addAll -> add......... 
     } 
     return puzzle;//........return puzzle......... 
     }