Android工程获取包内的MD5值

Android工程获取包内的MD5值

public static String getSignMd5Str()
{
    if (md5 == "")
    {
        try {
            PackageInfo packageInfo = app.getPackageManager().getPackageInfo(app.getPackageName(), PackageManager.GET_SIGNATURES);
            Signature[] signs = packageInfo.signatures;
            Signature sign = signs[0];
            String signStr = encryptionMD5(sign.toByteArray());
            md5 = signStr;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
    }

    return md5;

}

public static String encryptionMD5(byte[] byteStr) {
    MessageDigest messageDigest = null;
    StringBuffer md5StrBuff = new StringBuffer();
    try {
        messageDigest = MessageDigest.getInstance("MD5");
        messageDigest.reset();
        messageDigest.update(byteStr);
        byte[] byteArray = messageDigest.digest();
        for (int i = 0; i < byteArray.length; i++) {
            if (Integer.toHexString(0xFF & byteArray[i]).length() == 1) {
                md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));
            } else {
                md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));
            }
        }
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    }
    return md5StrBuff.toString();
}