如何计算文件中单词的长度？爪哇

我正在尝试编写一个代码来计算文件中特定长度的单词数。

例如：

How are you?

会打印：

Proportion of 3-letter words: 100%  (3 words)

我想计算长度为 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13+ 的单词

你能指导一下吗？

我并不是想找出单词数。我已经能够使用这段代码：

public static int WordCount() throws FileNotFoundException
{
    File file = new File("sample.txt");
    Scanner keyboard = new Scanner(new FileInputStream(file));
    int count=0;
    while(keyboard.hasNext())
    {
      keyboard.next();
      count++;
    }
    return count;
}

我想找到一定长度的单词.

UPDATE

我编写了以下代码：

public static int WordLengthCount() throws FileNotFoundException
{
  File file = new File("hello.txt");
  Scanner keyboard = new Scanner(new FileInputStream(file));
  int count5 = 0;
  int hell = 0; //This is just for the else command to compile

  while(keyboard.hasNext())
  {
    if ( keyboard.next().length() == 5 )
    {
      count5++;
      keyboard.next();
      return count5;
    }
  } return hell;
}

您可以使用length() http://docs.oracle.com/javase/8/docs/api/java/lang/String.html#length--方法计算字符串（单词）中的字符数。从那时起，只需将其保存在某个地方即可。例如，在Map:

public static Map<Integer, Integer> lengthCounts() throws FileNotFoundException
    Map<Integer, Integer> countMap = new HashMap<>();
    while(keyboard.hasNext())
    {
        String word = keyboard.next();
        int length = word.length();
        Integer currCount = countMap.get(length);
        if (currCount == null) {
            countMap.put (length, 1);
        else {
            countMap.put (length, currCount + 1);
        }
    }
    return countMap;
}

现在您可以检查任意特定长度的单词数，甚至打印所有单词。

EDIT:
如果您唯一需要的是特定长度的单词的百分比，那么您只需要两个计数器 - 一个用于该长度的单词，另一个用于所有单词：

public static double lengthPercentage(int requiredLength) throws FileNotFoundException
    int allWords = 0;
    int requiredWords = 0;
    while(keyboard.hasNext())
    {
        String word = keyboard.next();
        int length = word.length();
        if (length == requiredLength) {
            ++requiredWords;
        }
        ++allWords;
    }
    // implicit assumption: there's at least on word in the file
    return ((double) requiredWords) / allWords;
}