Question

I need help displaying only text from within a file that begins with lets say the word “Hello” and ends at the word “Bye”. I’m able to scan the whole text file and print it, but I need it to only print out a specific range defined by two variables. This is what I have so far, any tips will be appreciated. Thanks! 🙂

public static void main(String[] args) {
    // TODO code application logic here
    File fileName = new File("hello.txt");
    try {
        Scanner scan = new Scanner(fileName);
        while (scan.hasNextLine()) {
            String line = scan.nextLine();
            System.out.println(line);
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
}

Answer 1

How big is the file? I unless its large, read the file as a string and cut out the bit you want.

File file = new File("Hello.txt");
FileInputStream fis = new FileInputStream(file);
byte[] bytes = new byte[(int) file.length()];
fis.read(bytes);
fis.close();
String text = new String(bytes, "UTF-8");
System.out.println(text.substring(text.indexOf("START"), text.lastIndexOf("END")));

Using Apache FileUtils

String text = FileUtils.readFileToString("hello.txt");
System.out.println(text.substring(text.indexOf("START"), text.lastIndexOf("END")));