JAVA8-增强版Comparator进行排序

1、单条件升序：
list.sort(Comparator.comparing(User::getId);
2、降序：
list.sort(Comparator.comparing(User::getId).reversed());
3、多条件升序排序：
list.sort(Comparator.comparing(User::getId).thenComparing(User::getName));
4、用 Collections.reverse 反转一个 List
list.sort(Comparator.comparing(User::getId);
Collections.reverse(list);
等价于
list.sort(Comparator.comparing(User::getId).reversed());