list.sort()实现升序、降序排列_list.sort降序

实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {
    /**
     * 学号
     */
    private String no;
    /**
     * 姓名
     */
    private String name;
}

测试

@Test
public static void main(String[] args) {
     List<Student> list = new ArrayList();
     list.add(new Student("1","s1"));
     list.add(new Student("6","s6"));
     list.add(new Student("3","s3"));
     list.add(new Student("2","s2"));
     System.out.println("******原序******");
     System.out.println(list.toString());
     System.out.println("======升序======");
     //升序 默认升序
     //list.sort((o1,o2) -> 1 * o1.getNo().compareTo(o2.getNo()));
     list.sort((o1,o2) -> o1.getNo().compareTo(o2.getNo()));
     System.out.println(list.toString());
     System.out.println("-------降序-------");
     //降序
     list.sort((o1,o2) -> -1 * o1.getNo().compareTo(o2.getNo()));
     System.out.println(list.toString());
}

输出结果