1.         Integer[] arr = {10, 12, 45, 78, 551, 36, 45, 21};
    2. //        Comparator 比较器对象
    3.         Arrays.sort(arr);
    4.         System.out.println("Arrays.toString(arr) = " + Arrays.toString(arr));
    6.         // 降序
    7.         Arrays.sort(arr, new Comparator<Integer>() {
    8.             @Override
    9.             public int compare(Integer o1, Integer o2) {
    10.                 return o2-o1;
    11.             }
    12.         });
    13.         System.out.println("Arrays.toString(arr) = " + Arrays.toString(arr));
    14.     }