比JDK高效的array equals

private static boolean arrEquals(byte[] a1, byte[] a2) {
        if (a1 == a2)
            return true;

        if (a1 == null || a2 == null)
            return false;

        int length = a1.length;
        if (a2.length != length)
            return false;

        int j = 0, k = 1;
        while (j < length) {
            if (a1[j] != a2[j])
                return false;
            j += 2;
        }
        while (k < length) {
            if (a1[k] != a2[k])
                return false;
            k += 2;
        }
        return true;
    }