Question

I am trying to create a file and keep on appending into that file. In my code file is getting created but It is not appending anything in that file. Don’t know why? Can anyone suggest me what wrong I am doing..

Updated Code:-

        File file =new File("D://GeoData1.txt");

    BufferedWriter out = new BufferedWriter(new FileWriter(file, true));


    int j = -1;
    while(true) {           
        j++;
        String ipAddress = generateIPAddress(j);
        try {
            out.write(ipAddress);
            System.out.println(ipAddress);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                    out.flush();
                    out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }

Answer 1

Are you closing the writer?

finally {
   bufferWritter.close();
}

Update:

If you are using Java 7, try this:

final int NUMBER_OF_IPS_TO_APPEND = 5000; // or whatever size
Charset charset = Charset.defaultCharset();
Path file = Paths.get("myfile.txt");

try (BufferedWriter writer = Files.newBufferedWriter(file, charset,
                StandardOpenOption.CREATE,
                StandardOpenOption.APPEND)) {
    for (int i = 1; i <= NUMBER_OF_IPS_TO_APPEND; i++) {
        String ip = generateIPAddress(i);
        System.out.printf("Generated ip: %s\n", ip);
        writer.append(ip + "\n");
    }
} catch (IOException x) {
    System.err.format("IOException: %s\n", x);
}

Code adapted from The Java Tutorials.

Check if the IPS are being printed to the console and the file.

Fully working code with a mock implementation of generateIPAddress. It appends 5000 random IPv4 addresses (not checking for validity) to myfile.txt everytime it is executed.