How to convert zip file into bytes in Java

Question

how can I convert a zip file into bytes?

 byte[] ba;
 InputStream is = new ByteArrayInputStream(ba);
 InputStream zis = new ZipInputStream(is);

Answer 1

You can read a file from disk into a byte[] using

 byte[] ba = java.nio.file.Files.readAllBytes(filePath);

This is available from Java 7.

Answer 2

The basic principle is to feed the InputStream into the OutputStream, for example...

byte bytes[] = null;
try (FileInputStream fis = new FileInputStream(new File("..."))) {
    try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
        byte[] buffer = new byte[1024];
        int read = -1;
        while ((read = fis.read(buffer)) != -1) {
            baos.write(buffer, 0, read);
        }
        bytes = baos.toByteArray();
    } 
} catch (IOException exp) {
    exp.printStackTrace();
}