Error encoding files with MIME

Question

I have made a class to encode and decode files for base64. This class works. Im trying to do the same with MIME encoders and decoders but it doesnt´work and i dont know why.

  public void encode64(File input, File output) throws IOException{

    FileInputStream inputStream = new FileInputStream( input);
    FileOutputStream outputStream = new FileOutputStream( output);

    byte buff[] = new byte[300];
    int r = 0;

    while ( ( r = inputStream.read( buff)) > 0 ) {
      byte[] realBuff = Arrays.copyOf( buff, r );
      String b64 = Base64.getEncoder().encodeToString( realBuff);
      outputStream.write( b64.getBytes());
    }

    inputStream.close();
    outputStream.close();

}

public void decode64(File input, File output) throws IOException{

  FileInputStream inputStream = new FileInputStream( input);
  FileOutputStream outputStream = new FileOutputStream( output);

  byte buff[] = new byte[300];
  int r = 0;

  while ( ( r = inputStream.read( buff)) > 0 ) {
    byte[] realBuff = Arrays.copyOf( buff, r );
    outputStream.write( Base64.getDecoder().decode( realBuff));
  }

  inputStream.close();
  outputStream.close();

}

i have change the line from encode64 method

String b64 = Base64.getEncoder().encodeToString( realBuff);

for

String b64 = Base64.getMimeEncoder().encodeToString( realBuff);

and from the line of decode64 method

outputStream.write( Base64.getDecoder().decode( realBuff));

for

outputStream.write( Base64.getMimeDecoder().decode( realBuff));

And my class only works with txt files.

Answer 1

The method "Base64.getMimeEncoder().encodeToString(xxxx)" returns the Encoder that encodes using MIME type base64 encoding scheme while "Base64.getEncoder().encodeToString(xxxx)" uses Basic Type base64 encoding scheme. By default mime is: text/plain. Please refer url: https://en.wikipedia.org/wiki/MIME for further reference

Answer 2

I would try to use the wrap(...) method of Encoder/Decoder, ie

public void encode64(File input, File output) throws IOException {
    FileInputStream inputStream = new FileInputStream(input);
    FileOutputStream outputStream = new FileOutputStream(output);
    OutputStream encodedStream = Base64.getEncoder().wrap(outputStream);

    byte buff[] = new byte[300];
    int r = 0;
    while ((r = inputStream.read(buff)) > 0) {
      byte[] realBuff = Arrays.copyOf(buff, r);
      encodedStream.write(realBuff);
    }

    inputStream.close();
    encodedStream.close();
}

public void decode64(File input, File output) throws IOException {
  FileInputStream inputStream = new FileInputStream(input);
  FileOutputStream outputStream = new FileOutputStream(output);
  OutputStream decodedStream = Base64.getDecoder().wrap(outputStream);

  byte buff[] = new byte[300];
  int r = 0;
  while ((r = inputStream.read(buff)) > 0) {
    byte[] realBuff = Arrays.copyOf(buff, r);
    decodedStream.write(realBuff);
  }

  inputStream.close();
  decodedStream.close();
}

Disclaimer: written out of my head, not tested.