代码如下，作用如标题所述

1 public class HeapSort { 2     //方法作用:取出list里面的最小的 k 个值 3     public static 
     
      > List
      
        sort(List
       
         list, int k) throws Exception { 4         if (k <= 0) { 5             throw new Exception("k 必须大于0"); 6         } 7         if (list.size() < k) { 8             throw new Exception("list 长度必须大于k"); 9         }10         List
        
          heapList = new ArrayList
         
          (k);11         for (int i = 0; i < k; i ++) {12             heapList.add(list.get(i));13         }14         initialHeap(heapList);15         for (int i = k; i < list.size(); i ++) {16             if (list.get(i).compareTo(heapList.get(0)) < 0) {17                 heapList.set(0, list.get(i));18                 heapify(heapList, k, 0);19             }20         }21         return heapList;22     }23     private static 
          
           > void initialHeap(List
           
             list) {24 int n = list.size();25 // Build heap (rearrange array)26 for (int i = n / 2 - 1; i >= 0; i--)27 heapify(list, n, i);28 }29 private static 
            
             > void heapify(List
             
               list, int n, int i)30 {31 int largest = i; // Initialize largest as root32 int l = 2*i + 1; // left = 2*i + 133 int r = 2*i + 2; // right = 2*i + 234 35 // If left child is larger than root36 if (l < n && (list.get(l).compareTo(list.get(largest)) > 0))37 largest = l;38 39 // If right child is larger than largest so far40 if (r < n && (list.get(r).compareTo(list.get(largest)) > 0))41 largest = r;42 43 // If largest is not root44 if (largest != i)45 {46 T swap = list.get(i);47 list.set(i, list.get(largest));48 list.set(largest, swap);49 // Recursively heapify the affected sub-tree50 heapify(list, n, largest);51 }52 }53 }