String string = "[1, 6, 7, 2, 1, 9, 2, 49, 54, 47]";
            List<Integer> integers = new ArrayList<>();
            char[] chars = string.toCharArray();
            for (int i = 0; i < string.length(); i++) {
                if (Character.isDigit(chars[i])) {
                    integers.add(Character.getNumericValue(chars[i]));
                }
            }
            System.out.println(Arrays.toString(integers.stream().mapToInt(i -> i).toArray()));