java实现快速排序算法

public static void quickSortByMid(int[] a, int low, int high) {
    if (low >= high)
      return;
    // 分割
    int pivot = a[low];// 基准值
    int i = low, j = high;
    while (i < j) {
      while (i < j && a[j] >= pivot)
        --j;
      a[i]=a[j];
      while (i < j && a[i] <= pivot)
        ++i;
      a[j]=a[i];
    }
    a[i]=pivot;
    quickSortByMid(a, low, i-1);
    quickSortByMid(a, i+1, high);
  }