1 package day7.lesson2;
2
3 import java.util.ArrayList;
4 import java.util.Collections;
5 import java.util.Comparator;
6
7 /*
8 2.2 案例-ArrayList集合存储学生并排序
9 ArrayList存储学生对象，使用Collections对ArrayList进行排序
10 要求：按照年龄从小到大排序，年龄相同时，按照姓名的字母顺序排序
11 */
12 public class CollectionsDemo2 {
13 public static void main(String[] args) {
14 ArrayList<Student> arrayList = new ArrayList<>();
15
16 Student s1 = new Student("xiyangyang", 11);
17 Student s2 = new Student("lanyangyang", 13);
18 Student s3 = new Student("feiyangyang", 15);
19 Student s4 = new Student("meiyangyang", 11);
20
21 arrayList.add(s1);
22 arrayList.add(s2);
23 arrayList.add(s3);
24 arrayList.add(s4);
25
26 //使用Collections对ArrayList集合排序
27 //sort•(List<T> list, Comparator<? super T> c)
28 Collections.sort(arrayList, new Comparator<Student>() { //匿名内部类比较器
29 @Override
30 public int compare(Student s1, Student s2) {
31 int num = s1.getAge() - s2.getAge();
32 int num2 = (num==0 ? s1.getName().compareTo(s2.getName()) : num);
33 return num2;
34 }
35 });
36
37 for (Student s: arrayList){
38 System.out.println(s.getName() + "," + s.getAge());
39 }
40 }
41 }
1 package day7.lesson2;
2
3 public class Student {
4
5 private String name;
6 private int age;
7
8 public Student() {
9 }
10
11 public Student(String name, int age) {
12 this.name = name;
13 this.age = age;
14 }
15
16 public void setName(String name) {
17 this.name = name;
18 }
19
20 public void setAge(int age) {
21 this.age = age;
22 }
23
24 public String getName() {
25 return name;
26 }
27
28 public int getAge() {
29 return age;
30 }
31 }
