Convert InputStream to byte array in Java

Question

How do I read an entire InputStream into a byte array?

Answer 1

Wrap it in a DataInputStream if that is off the table for some reason, just use read to hammer on it until it gives you a -1 or the entire block you asked for.

public int readFully(InputStream in, byte[] data) throws IOException {
    int offset = 0;
    int bytesRead;
    boolean read = false;
    while ((bytesRead = in.read(data, offset, data.length - offset)) != -1) {
        read = true;
        offset += bytesRead;
        if (offset >= data.length) {
            break;
        }
    }
    return (read) ? offset : -1;
}