DigestUtils.java

package me.ele.amigo.utils;

import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class DigestUtils {

    private static final int STREAM_BUFFER_LENGTH = 1024 * 8;

    private static MessageDigest getDigest(String algorithm) {
        try {
            return MessageDigest.getInstance(algorithm);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    private static MessageDigest getMd5Digest() {
        return getDigest("MD5");
    }

    private static byte[] digest(MessageDigest digest, InputStream data) throws IOException {
        byte[] buffer = new byte[STREAM_BUFFER_LENGTH];
        int read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);

        while (read > -1) {
            digest.update(buffer, 0, read);
            read = data.read(buffer, 0, STREAM_BUFFER_LENGTH);
        }

        return digest.digest();
    }

    public static byte[] md5(InputStream data) throws IOException {
        return digest(getMd5Digest(), data);
    }

}