Writing into file line by line

Question

I am reading data from text [utf8 format] file and store it in a string and convert that string into hexadecimal format and save this hexadecimal string into another file but I want to save this converted hexadecimal string line by line. How to do that?

        String sCurrentLine;
        br = new BufferedReader(new FileReader("demmo123.txt"));
        while ((sCurrentLine = br.readLine()) != null) {
            sb1.append(sCurrentLine);
        }
        String ss = sb1.toString();
        Scanner sc = new Scanner(ss);
        String helloWorldHex = toHexString(ss.getBytes());
        file = new File("demmo.txt");
        fop = new FileOutputStream(file);
        if (!file.exists()) {
            file.createNewFile();
        }
        byte[] contentInBytes = helloWorldHex.getBytes();
        fop.write(helloWorldHex.getBytes());
        fop.write(contentInBytes);
        fop.flush();
        fop.close();
        fop.write(helloWorldHex.getBytes());

Answer 1

For input data:

test string 1
test string 2
test string 3
test string 4


import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Example {
    public static void main(String[] args) {

        try {
            File input = new File("C:\\temp\\input.txt");
            File output = new File("C:\\temp\\output.txt");

            Scanner scanner = new Scanner(input);
            PrintWriter printer = new PrintWriter(output);
            while(scanner.hasNextLine()) {
                String string = scanner.nextLine();
                StringBuilder stringBuilder = new StringBuilder(200);
                for(char ch: string.toCharArray()) {
                    if(stringBuilder.length() > 0) stringBuilder.append(' ');
                    stringBuilder.append(String.format("%04x", (int)ch));
                }
                printer.write(stringBuilder.toString());                    
                printer.write("\r\n");
            }
            printer.flush();
            printer.close();
        }
        catch(FileNotFoundException e) {
            System.err.println("File not found.");
        }
    }

}

it gives:

0074 0065 0073 0074 0020 0073 0074 0072 0069 006e 0067 0020 0031
0074 0065 0073 0074 0020 0073 0074 0072 0069 006e 0067 0020 0032
0074 0065 0073 0074 0020 0073 0074 0072 0069 006e 0067 0020 0033
0074 0065 0073 0074 0020 0073 0074 0072 0069 006e 0067 0020 0034

Answer 2

FileWriter writer = new FileWriter("outputfile.txt"); // use your file extension
String content = "My first line";
writer.write(content+"\n");
writer.flush();
//if you have array of string use for loop 
writer.close();
// you should use exception handing always and import relevant classes