如何根据字符数组中的数字对其进行排序

public class QuickSort {
    public static void quickSort(char[] arr, int low, int high) {
        if (low < high) {
            int pivot = partition(arr, low, high);
            quickSort(arr, low, pivot - 1);
            quickSort(arr, pivot + 1, high);
        }
    }

    public static int partition(char[] arr, int low, int high) {
        char pivot = arr[low];
        while (low < high) {
            while (low < high && arr[high] >= pivot) {
                high--;
            }
            arr[low] = arr[high];
            while (low < high && arr[low] <= pivot) {
                low++;
            }
            arr[high] = arr[low];
        }
        arr[low] = pivot;
        return low;
    }

    public static void main(String[] args) {
        char[] arr = {'3', '1', '4', '1', '5', '9', '2', '6', '5'};
        quickSort(arr, 0, arr.length - 1);
        System.out.println(Arrays.toString(arr));
    }
}