一件货物,具有两个属性，价格和重量，按照价格低优先，重量高优先原则排序

一、实现Comparable接口

package com.learn.bean;

public class Goods implements Comparable{

    private Integer price;

    private Integer kg;

    public Integer getPrice() {
        return price;
    }

    public void setPrice(Integer price) {
        this.price = price;
    }

    public Integer getKg() {
        return kg;
    }

    public void setKg(Integer kg) {
        this.kg = kg;
    }

    public Goods(Integer price, Integer kg) {
        this.price = price;
        this.kg = kg;
    }

    public Goods() {

    }

    @Override
    public String toString() {
        return "Goods{" +
                "price=" + price +
                ", kg=" + kg +
                '}';
    }

    @Override
    public int compareTo(Object o) {
        if(o instanceof Goods) {
            Goods other = (Goods) o;
            if (this.price > other.price) {
                return 1;
            } else if (this.price < other.price) {
                return -1;
            }else{
                if(this.kg<other.kg){
                    return 1;
                }else if (this.kg>other.kg){
                    return -1;
                }else {
                    return 0;
                }
            }
//            return 0;
        }
        throw new RuntimeException("输入的数据类型不一致");
    }
}

测试代码

package com.learn.test;

import com.learn.bean.Goods;
import com.learn.bean.User;

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

public class CompareTest {

    public static void main(String[] args) {
        Goods goods1 = new Goods(10, 100);
        Goods goods2 = new Goods(10, 200);
        Goods goods3 = new Goods(20, 100);
        Goods goods4 = new Goods(20, 200);

        ArrayList<Goods> goods = new ArrayList<>();
        goods.add(goods1);goods.add(goods2);goods.add(goods3);goods.add(goods4);

        Collections.sort(goods);

        System.out.println(goods);
    }
}

二、实现Comparator接口

package com.learn.bean;

public class Goods{

    private Integer price;

    private Integer kg;

    public Integer getPrice() {
        return price;
    }

    public void setPrice(Integer price) {
        this.price = price;
    }

    public Integer getKg() {
        return kg;
    }

    public void setKg(Integer kg) {
        this.kg = kg;
    }

    public Goods(Integer price, Integer kg) {
        this.price = price;
        this.kg = kg;
    }

    public Goods() {

    }

    @Override
    public String toString() {
        return "Goods{" +
                "price=" + price +
                ", kg=" + kg +
                '}';
    }

}

编写一个类

package com.learn.bean;

import java.util.Comparator;

public class CC extends Goods implements Comparator<Goods> {

    @Override
    public int compare(Goods o1, Goods o2) {
        if(o1.getPrice()>o2.getPrice()){
            return 1;
        }else if (o1.getPrice()<o2.getPrice()){
            return -1;
        }else {
            if(o1.getKg()<o2.getKg()){
                return 1;
            }else if(o1.getKg()>o2.getKg()){
                return -1;
            }else {
                return 0;
            }
        }
    }
}

测试代码

package com.learn.test;

import com.learn.bean.CC;
import com.learn.bean.Goods;
import com.learn.bean.User;

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

public class CompareTest {

    public static void main(String[] args) {
        Goods goods1 = new Goods(10, 100);
        Goods goods2 = new Goods(10, 200);
        Goods goods3 = new Goods(20, 100);
        Goods goods4 = new Goods(20, 200);

        ArrayList<Goods> goods = new ArrayList<>();
        goods.add(goods1);goods.add(goods2);goods.add(goods3);goods.add(goods4);

        Collections.sort(goods,new CC());

        System.out.println(goods);
    }
}