對ArrayList中的Person對象按照先年齡從大到小,相同年齡的再按照姓名（姓名是英文的）的字母順序進行排序.

ListDemo2.java
-----------------
package com.fs.test;

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

/*
 * Collections可以針對ArrayList存儲基本包裝類的元素排序，存儲自定義對象可不可以排序呢?
 */
public class Listdemo2 {
    public static void main(String[] args) {
        // 創建集合對象
        List<Person2> list = new ArrayList<Person2>();

        Person2 s1 = new Person2("Bobby",18);
        Person2 s2 = new Person2("Mike",20);
        Person2 s3 = new Person2("Jim",35);
        Person2 s4 = new Person2("Zoe",27);
        Person2 s5 = new Person2("Dave",18);
        Person2 s6 = new Person2("Madison",35);
        Person2 s7 = new Person2("Caden",40);
        Person2 s8 = new Person2("Ava",23);
        Person2 s9 = new Person2("Noah",25);
        Person2 s10 = new Person2("Isabella",27);
        Person2 s11 = new Person2("Lucas",25);
 
        // 添加元素對象
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s4);
        list.add(s5);
        list.add(s6);
        list.add(s7);
        list.add(s8);
        list.add(s9);
        list.add(s10);
        list.add(s11);
 
        // 排序
        // 自然排序
        // Collections.sort(list);
        // 比較器排序
        // 如果同時有自然排序和比較器排序，以比較器排序為主
        Collections.sort(list, new Comparator<Person2>() {
            @Override
            public int compare(Person2 s1, Person2 s2) {
                  if(s1.getAge()-(s2.getAge())!=0){
                       return s1.getAge()-(s2.getAge());
                    }else{
                       return  s1.getName().compareTo(s2.getName());
                     }
            }
        });
 
        // 遍歷集合
        for (Person2 s : list) {
            System.out.println(s.getName() + "---" + s.getAge());
        }
    }
}

Person2,java
-------------------package com.fs.test;

public class Person2  {
    private String name;
    private int age;
 
    public Person2() {
        super();
    }
 
    public Person2(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public int getAge() {
        return age;
    }
 
    public void setAge(int age) {
        this.age = age;
    }
}