converting DataHandler to byte[]

Question

I need a code snippt for converting DataHandler to byte[].

This data handler contains Image.

Answer 1

It can be done by using below code without much effort using apache IO Commons.

final InputStream in = dataHandler.getInputStream();
byte[] byteArray=org.apache.commons.io.IOUtils.toByteArray(in);

Answer 2

You can do it like this:

public static byte[] toBytes(DataHandler handler) throws IOException {
    ByteArrayOutputStream output = new ByteArrayOutputStream();
    handler.writeTo(output);
    return output.toByteArray();
}

Answer 3

private static final int INITIAL_SIZE = 1024 * 1024;
private static final int BUFFER_SIZE = 1024;

public static byte[] toBytes(DataHandler dh) throws IOException {
    ByteArrayOutputStream bos = new ByteArrayOutputStream(INITIAL_SIZE);
    InputStream in = dh.getInputStream();
    byte[] buffer = new byte[BUFFER_SIZE];
    int bytesRead;
    while ( (bytesRead = in.read(buffer)) >= 0 ) {
        bos.write(buffer, 0, bytesRead);
    }
    return bos.toByteArray();
}

Beware that ByteArrayOutputStream.toByteArray() creates a copy of the internal byte array.