1 package cn.itcast_02; 2  3 import java.util.ArrayList; 4 import java.util.Collections; 5 import java.util.Comparator; 6 import java.util.List; 7 public class CollectionsDemo { 8     public static void main(String[] args) { 9         // 创建集合对象10         List<Student> list = new ArrayList<Student>();11 12         // 创建学生对象13         Student s1 = new Student("林青霞", 27);14         Student s2 = new Student("风清扬", 30);15         Student s3 = new Student("刘晓曲", 28);16         Student s4 = new Student("武鑫", 29);17         Student s5 = new Student("林青霞", 27);18 19         // 添加元素对象20         list.add(s1);21         list.add(s2);22         list.add(s3);23         list.add(s4);24         list.add(s5);25 26         // 排序27         // 自然排序28         // Collections.sort(list);29         // 比较器排序30         // 如果同时有自然排序和比较器排序，以比较器排序为主31         Collections.sort(list, new Comparator<Student>() {32             @Override33             public int compare(Student s1, Student s2) {34                 int num = s2.getAge() - s1.getAge();35                 int num2 = num == 0 ? s1.getName().compareTo(s2.getName())36                         : num;37                 return num2;38             }39         });40 41         // 遍历集合42         for (Student s : list) {43             System.out.println(s.getName() + "---" + s.getAge());44         }45     }46 }