ตัวอย่างนี้มาจาก https://www.geeksforgeeks.org/counting-number-lines-words-characters-paragraphs-text-file-using-java/ จากตัวอย่างจะเป็นการใช้งานออบเจกต์ FileInputStream เพื่อเชื่อมต่อกับออบเจกต์ File และใช้ออบเจกต์ BufferReader เพื่อเพิ่มความเร็วในการอ่านไฟล์ 

// Java program to count the
// number of characters in a file
import java.io.*;

public class Test
{
    public static void main(String[] args) throws IOException
    {
        File file = new File("C:\\Users\\Mayank\\Desktop\\1.txt");
        FileInputStream fileStream = new FileInputStream(file);
        InputStreamReader input = new InputStreamReader(fileStream);
        BufferedReader reader = new BufferedReader(input);

        String line;

        // Initializing counters
        int countWord = 0;
        int sentenceCount = 0;
        int characterCount = 0;
        int paragraphCount = 1;
        int whitespaceCount = 0;

        // Reading line by line from the
        // file until a null is returned
        while((line = reader.readLine()) != null)
        {
            if(line.equals(""))
            {
                paragraphCount++;
            } else {
                characterCount += line.length();

                // \\s+ is the space delimiter in java
                String[] wordList = line.split("\\s+");

                countWord += wordList.length;
                whitespaceCount += countWord -1;

                // [!?.:]+ is the sentence delimiter in java
                String[] sentenceList = line.split("[!?.:]+");

                sentenceCount += sentenceList.length;
            }
        }

        System.out.println("Total word count = " + countWord);
        System.out.println("Total number of sentences = " + sentenceCount);
        System.out.println("Total number of characters = " + characterCount);
        System.out.println("Number of paragraphs = " + paragraphCount);
        System.out.println("Total number of whitespaces = " + whitespaceCount);
    }
}

ผลลัพธ์คือ

Total word count = 5
Total number of sentences = 3
Total number of characters = 21
Number of paragraphs = 2
Total number of whitespaces = 7