MD5.java

package com.yuyh.library.utils.data.safe;

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

/**
 * MD5加密
 *
 * @author yuyh.
 * @date 16/4/9.
 */
public class MD5 {
    private static final String TAG = MD5.class.getSimpleName();
    private static final int STREAM_BUFFER_LENGTH = 1024;

    public static MessageDigest getDigest(final String algorithm) throws NoSuchAlgorithmException {
        return MessageDigest.getInstance(algorithm);
    }

    public static byte[] md5(String txt) {
        return md5(txt.getBytes());
    }

    public static byte[] md5(byte[] bytes) {
        try {
            MessageDigest digest = getDigest("MD5");
            digest.update(bytes);
            return digest.digest();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static byte[] md5(InputStream is) throws NoSuchAlgorithmException, IOException {
        return updateDigest(getDigest("MD5"), is).digest();
    }

    public static MessageDigest updateDigest(final MessageDigest digest, final InputStream data) throws IOException {
        final 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;
    }

    /**
     * 使用MD5算法对传入的key进行加密并返回。
     */
    public static String getMD5(String key) {
        String cacheKey;
        try {
            final MessageDigest mDigest = MessageDigest.getInstance("MD5");
            mDigest.update(key.getBytes());
            cacheKey = bytesToHexString(mDigest.digest());
        } catch (NoSuchAlgorithmException e) {
            cacheKey = String.valueOf(key.hashCode());
        }
        return cacheKey;
    }

    private static String bytesToHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < bytes.length; i++) {
            String hex = Integer.toHexString(0xFF & bytes[i]);
            if (hex.length() == 1) {
                sb.append('0');
            }
            sb.append(hex);
        }
        return sb.toString();
    }
}