10 Ways to Read Files using Java Code

Table of Contents

1. Using Scanner
2. Using InputStream
3. Using BufferedReader
4. Using FileInputStream
5. Using InputStreamReader
6. Using Files.newInputStream
7. Using FileChannel
8. Using FileReader
9. Using DataInputStream
10. Using RandomAccessFile

1. Using Scanner

    Scanner scanner = new Scanner(new File("data.txt"));
    while (scanner.hasNextLine()) {
        String line = scanner.nextLine();
        System.out.println(line);
    }
    scanner.close();
    

2. Using InputStream

    InputStream inputStream = new FileInputStream("data.txt");
    int data = inputStream.read();
    while(data != -1) {
        System.out.print((char) data);
        data = inputStream.read();
    }
    inputStream.close();
    

3. Using BufferedReader

    BufferedReader reader = new BufferedReader(new FileReader("data.txt"));
    String line;
    while ((line = reader.readLine()) != null) {
        System.out.println(line);
    }
    reader.close();
    

4. Using FileInputStream

    FileInputStream fis = new FileInputStream("data.txt");
    byte[] buffer = new byte[10];
    StringBuilder sb = new StringBuilder();
    while (fis.read(buffer) != -1) {
        sb.append(new String(buffer));
        buffer = new byte[10];
    }
    fis.close();
    System.out.println(sb.toString());
    

5. Using InputStreamReader

    FileInputStream fis = new FileInputStream("data.txt");
    InputStreamReader isr = new InputStreamReader(fis);
    char[] buffer = new char[10];
    StringBuilder sb = new StringBuilder();
    while (isr.read(buffer) != -1) {
        sb.append(new String(buffer));
        buffer = new char[10];
    }
    isr.close();
    System.out.println(sb.toString());
    

6. Using Files.newInputStream

    Path path = Paths.get("data.txt");
    try (InputStream in = Files.newInputStream(path)) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
    }
    

7. Using FileChannel

    RandomAccessFile aFile = new RandomAccessFile("data.txt", "r");
    FileChannel inChannel = aFile.getChannel();
    ByteBuffer buffer = ByteBuffer.allocate(1024);
    while(inChannel.read(buffer) > 0) {
        buffer.flip();
        for (int i = 0; i < buffer.limit(); i++) {
            System.out.print((char) buffer.get());
        }
        buffer.clear();
    }
    inChannel.close();
    aFile.close();
    

8. Using FileReader

    FileReader fr = new FileReader("data.txt");
    int i;
    while ((i = fr.read()) != -1)
        System.out.print((char) i);
    fr.close();
    

9. Using DataInputStream

    DataInputStream dis = new DataInputStream(new FileInputStream("data.txt"));
    byte[] datainBytes = new byte[dis.available()];
    dis.readFully(datainBytes);
    dis.close();
    String content = new String(datainBytes, 0, datainBytes.length);
    System.out.println(content);
    

10. Using RandomAccessFile

    RandomAccessFile file = new RandomAccessFile("data.txt", "r");
    String str;
    while ((str = file.readLine()) != null) {
        System.out.println(str);
    }
    file.close();