Java 用Comparator对ArrayList中的对象按照该对象某属性排序

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

/**
 * Created by LSK.Reno on 2018/7/1.
 */


public class ComparableTest {
    public static void main(String[] args) {
        Comparator<Student> comparator = new Comparator<Student>(){
            public int compare(Student s1, Student s2) {
                //先排年龄
                if(s1.age!=s2.age){
                    return s2.age-s1.age;
                }
                else{
                    //年龄相同则按姓名排序