请帮我写一段JAVA的快速排序

好的，以下是快速排序的JAVA代码示例：

public class QuickSort {
    public static void main(String[] args) {
        int[] arr = {10, 80, 30, 90, 40, 50, 70};
        int size = arr.length;
        quickSort(arr, 0, size - 1);

        System.out.println("排序后的数组：");
        for (int i = 0; i < size; ++i) {
            System.out.print(arr[i] + " ");
        }
    }

    public static void quickSort(int[] arr, int left, int right) {
        if (left < right) {
            int partitionIndex = partition(arr, left, right);
            quickSort(arr, left, partitionIndex - 1);
            quickSort(arr, partitionIndex + 1, right);
        }
    }

    public static int partition(int[] arr, int left, int right) {
        int pivot = arr[right];
        int i = (left - 1);

        for (int j = left; j < right; j++) {
            if (arr[j] <= pivot) {
                i++;

                int temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }

        int temp = arr[i + 1];
        arr[i + 1] = arr[right];
        arr[right] = temp;

        return i + 1;
    }
}

以上就是快速排序的JAVA代码示例。