使用stream流实现排序

sorted()默认升序

list.stream().sorted().collect(Collectors.toList());

单独实现以某属性降（升）序

降序才加.reversed()

list.stream().sorted(Comparator.comparing(Student::getAge).reversed()).collect(Collectors.toList());

先以年龄升序排序,年龄相同是 按分数降序

List<Student> list= userList.stream().sorted(Comparator.comparing(Student::getAge)
					.thenComparing(Student::getScore,Comparator.reverseOrder())).collect(Collectors.toList());