最简单之获取app签名md5值

网上教的大多数获取app签名md5值的方法都是通过生成jks还得打开黑窗口，有点小麻烦所以我用代码写了一个获取签名的方法

 /**
     * MD5加密
     * @param byteStr 需要加密的内容
     * @return 返回 byteStr的md5值
     */
    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();
    }
    /**
     * 获取app签名md5值
     */
    public String getSignMd5Str() {
        try {
            PackageInfo packageInfo = getPackageManager().getPackageInfo(getPackageName(), PackageManager.GET_SIGNATURES);
            Signature[] signs = packageInfo.signatures;
            Signature sign = signs[0];
            String signStr = encryptionMD5(sign.toByteArray());
            return signStr;
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        return "";
    }

最后通过getSignMd5Str()，，，，，返回一个String signMd5Str = getSignMd5Str();，，，，log打印一下就出来了