升序排序例子1——comparator

package test;

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

class Person {
    private String name;
    private int age;
    private double score;

    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;
    }

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }

    public Person(String name, int age, Double score) {

        this.name = name;
        this.age = age;
        this.score = score;
    }
    public String toString(){
        return String.format("name=%s,age=%d,score=%f",name,age,score);

    }}

public class CompareToDemo {
    public static void main(String[] args) {
        List<Person> list = new ArrayList<>();
        list.add(new Person("lisi",28,99.5));
        list.add(new Person("lisi",27,99.5));
        list.add(new Person("haokun",7,90.5));
        list.add(new Person("haokun",7,100.0));
        list.add(new Person("aoteman",28,95.0));
        Collections.sort(list,new Comparator<Person>(){
           public int compare(Person p1,Person p2){
               /** if(p1.getName().compareTo(p2.getName())!=0){
                    return p1.getName().compareTo(p2.getName());
                }else if(p1.getAge()-p2.getAge()!=0){
                    return p1.getAge()-p2.getAge();
                }else{
                    return (int)(p1.getScore()-p2.getScore());
                }*/

　　　　　　　　//写法的改进
　　　　　　　　int nameNum = p1.getName().compareTo(p2.getName());//比较姓名
　　　　　　　　int ageNum = nameNum == 0 ? p1.getAge() - p2.getAge() : nameNum;//比较年龄
　　　　　　　　int scoreNum = ageNum == 0 ? Floact.compare(p1.getScore(),p2.getScore()):ageNum;//比较分数

　　　　　　　　return scoreNum;
            }
        });
        for(Person p:list){
            System.out.println(p);

        }

    }
}