如何计算 java 中 pdf 文件中的字母数量

Question

在这个程序中，我需要统计所有字母（a-z）的个数，而下面的代码只能统计"u"的个数。那么如果我要数26，是否需要在for循环中写26个if语句？

输出应该是： a:389 b:777 c:909 .. ..

请给我其他解决方案

            String[] words = sourceCode.split(" ");
            amountOfWords = amountOfWords + words.length;
            for (String word : words) {
                amountOfChars = amountOfChars + word.length();

                for (int i = 0; i < word.length(); i++) {
                    if (word.charAt(i) == 'u' || word.charAt(i) == 'U') {
                        u++;
                    }
                }
            }

Answer 1

试试这个：

String str = new PDFTextStripper().getText(doc);    
int len = str.length();
Map<Character, Integer> numOfChars = new HashMap<Character, Integer>(Math.min(len, 26));

for (int i = 0; i < len; ++i)//pre increment
{
    char alphabet = str.charAt(i);    
    if (!numOfChars.containsKey(alphabet ))
    {
        numOfChars.put(alphabet , 1);
    }
    else
    {
        numOfChars.put(alphabet , numOfChars.get(alphabet ) + 1);
    }
}
System.out.println(numOfChars);

Source

Answer 2

你可以试试这个。我正在使用库：fontbox-2.0.12 和 pdfbox-2.0.12 和 commons-logging-1.2

        try {
            PDDocument doc = PDDocument.load(new File("E:\project-test\scloud\test\src\main\resources\Shadip_Banik.pdf"));
            String text = new PDFTextStripper().getText(doc);

            sourceCode = text.replace("-", "").replace(".", "");


            String[] words = sourceCode.split(" ");

            amountOfWords = amountOfWords + words.length;
            StringBuilder builder = new StringBuilder();

            for (String word : words) {
                amountOfChars = amountOfChars + word.length();

                Pattern pattern = Pattern.compile("[a-zA-Z]");
                Matcher matcher = pattern.matcher(word);
                //System.out.println("MatchesCount "+matcher.group());
                while (matcher.find()) {
                    builder.append(matcher.group());

                }
            }
            String allData = builder.toString();
            System.out.println(builder.toString());
            int total = 0;
            for (int i=0;i<allAlphabate.length();i++)
            {
                int alphabateCount = 0;
                Pattern pattern = Pattern.compile(Character.toString(allAlphabate.charAt(i)));
                Matcher matcher = pattern.matcher(allData);
                while (matcher.find()) {
                    alphabateCount++;
                }
                total+=alphabateCount;
                System.out.println(allAlphabate.charAt(i) +" : "+alphabateCount);
            }
            if(total == builder.toString().length())
            {
                System.out.println("Yes   -------------------------------------------------");
            }
            System.out.println("Amount of Chars is " + amountOfChars);
            System.out.println("Amount of Words is " + (amountOfWords + 1));
            System.out.println("Average Word Length is " + (amountOfChars / amountOfWords));
        } catch (Exception ert) {

        }

但是如果你想一起计算大写和小写，请使用此代码

     for (String word : words) {
                    amountOfChars = amountOfChars + word.length();

                    Pattern pattern = Pattern.compile("[a-zA-Z]");
                    Matcher matcher = pattern.matcher(word.toLowerCase());
                    //System.out.println("MatchesCount "+matcher.group());
                    while (matcher.find()) {
                        builder.append(matcher.group());

                    }
                }
                String allData = builder.toString();
                int total = 0;
                for (int i=0;i<allAlphabate.length();i++)
                {
                    int alphabateCount = 0;
                    Pattern pattern = Pattern.compile(Character.toString(allAlphabate.charAt(i)));
                    Matcher matcher = pattern.matcher(allData.toLowerCase());
                    while (matcher.find()) {
                        alphabateCount++;
                    }
                    total+=alphabateCount;
                    System.out.println(allAlphabate.charAt(i) +" : "+alphabateCount);
                }
                if(total == builder.toString().length())
                {
                    System.out.println("Yes   -------------------------------------------------");
}

如何计算 java 中 pdf 文件中的字母数量

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