JavaSE-16.2.2【案例-ArrayList集合存储学生并排序】

package day7.lesson2;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

/*
2.2 案例-ArrayList集合存储学生并排序
    ArrayList存储学生对象，使用Collections对ArrayList进行排序
    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
 */
public class CollectionsDemo2 {
    public static void main(String[] args) {
        ArrayList<Student> arrayList = new ArrayList<>();

        Student s1 = new Student("xiyangyang", 11);
        Student s2 = new Student("lanyangyang", 13);
        Student s3 = new Student("feiyangyang", 15);
        Student s4 = new Student("meiyangyang", 11);

        arrayList.add(s1);
        arrayList.add(s2);
        arrayList.add(s3);
        arrayList.add(s4);

        //使用Collections对ArrayList集合排序
        //sort•(List<T> list, Comparator<? super T> c)
        Collections.sort(arrayList, new Comparator<Student>() { //匿名内部类比较器
            @Override
            public int compare(Student s1, Student s2) {
                int num = s1.getAge() - s2.getAge();
                int num2 = (num==0 ? s1.getName().compareTo(s2.getName()) : num);
                return num2;
            }
        });

        for (Student s: arrayList){
            System.out.println(s.getName() + "," + s.getAge());
        }
    }
}

package day7.lesson2;

public class Student {

    private String name;
    private int age;

    public Student() {
    }

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}