Change CRT file to byte

Question

I need to convert a file .crt byte to be able to send by socket. This code works in Java, but how would I write it on Android?

Path path = Paths.get("sdcard/certificado.crt");
byte[] certificado = Files.readAllBytes(path);

Answer 1

Untested code

With my search I obtained the following:

public static byte[] convertFileToByteArray(File f)
{
    byte[] byteArray = null;
    try
    {
        InputStream inputStream = new FileInputStream(f);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        byte[] b = new byte[1024*8];
        int bytesRead =0;

        while ((bytesRead = inputStream.read(b)) != -1)
        {
            bos.write(b, 0, bytesRead);
        }
        byteArray = bos.toByteArray();
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }
    return byteArray;
}

Source: http://androidsnippets.wordpress.com/2012/08/07/how-to-convert-a-file-to-byte-array/

But I also found these:

https://stackoverflow.com/questions/14466469/convert-android-graphics-path-object-to-byte-and-back https://stackoverflow.com/questions/13466908/create-a-arraylist-of-byte-array-in-android

And the one I believe isn’t quite what you want, but it’s useful:

http://examples.javacodegeeks.com/core-java/io/fileoutputstream/write-byte-array-to-file-with-fileoutputstream/

Answer 2

Well, you can use the library Apache Commons to achieve this. Attention to the functions IOUtils.toByteArray(InputStream input) and FileUtils.readFileToByteArray(File file).

---

If you do not choose to use what was suggested above you can use this function below.

public static byte[] getFileBytes(File file) throws IOException {
    ByteArrayOutputStream ous = null;
    InputStream ios = null;
    try {
        byte[] buffer = new byte[4096];
        ous = new ByteArrayOutputStream();
        ios = new FileInputStream(file);
        int read = 0;
        while ((read = ios.read(buffer)) != -1)
            ous.write(buffer, 0, read);
    } finally {
        try {
            if (ous != null)
                ous.close();
        } catch (IOException e) {
            //
        }
        try {
            if (ios != null)
                ios.close();
        } catch (IOException e) {
            // 
        }
    }
    return ous.toByteArray();
}

_{Code found in this answer}

Answer 3

Sorry personal delay I managed to do a while ago only I forgot to post here my answer. My code was like this

    File f = new File(cert); // o cert é o caminho do meu certificado ex: sdcar/download/certificado.crt
    FileInputStream input = new FileInputStream(f);
    byte[] certificado = new byte[(int) f.length()];
    input.read(certificado);