JAVA | 33

任何情况下，只要是一组对象要排序，对象所在的类一定要实现 Comparable 接口，并且要覆写 CompareTo 方法。

import java.util.Arrays;class Book implements Comparable <Book>{    private String title;    private int price;    public Book(String title, int price){        this.title = title;        this.price = price;    }    @Override    public String toString() {        return this.title + " " + this.price;    }    @Override    public int compareTo(Book o) {  //Arrays.sort 会自动调用此方法进行比较。        if(this.price > o.price){            return 1;        }else if(this.price < o.price){            return -1;        }else {            return 0;        }    }}public class Main {    public static void main(String[] args) {        Book bookA= new Book("java",100);        Book bookB = new Book("python",80);        Book bookC = new Book("c ++",90);        Book bookD = new Book("javascript",100);        Book books [] = new Book []{bookA,bookB,bookC,bookD};        Arrays.sort(books);        System.out.println(Arrays.toString(books));    }}