练习——Arrays类小练

package com.arrays_;

import java.util.Arrays;
import java.util.Comparator;

public class ArraysExercise {
    public static void main(String[] args) {

        /*
        案例:自定义Book类，里面包含name和price，按price排序(从大到小)。
        要求使用两种方式排序 ，有一个 Book[] books = 4本书对象。
        使用前面学习过的传递 实现Comparator接口匿名内部类，也称为定制排序。[同学们完成这个即可 10min ]，
        可以按照 price (1)从大到小 (2)从小到大 (3)按照书名长度从大到小
         */

        Book[] books = new Book[4];  //声明一个数组对象
        books[0] = new Book("红楼梦",100);
        books[1] = new Book("金色的梅",90);
        books[2] = new Book("青年文摘20年",5);
        books[3] = new Book("java从入门到放弃~",300);

        //1.price 从大到小
        Arrays.sort(books, new Comparator() {
            @Override
            //这里是对Book数组排序，因此 o1 和 o2 就是Book对象
            public int compare(Object o1, Object o2) {
                Book book1 = (Book) o1;
                Book book2 = (Book) o2;
                double b1 = book1.getPrice();
                double b2 = book2.getPrice();
                if (b1>b2){
                    return -1;
                }else if (b1<b2){
                    return 1;
                }else {
                    return 0;
                }

            }
        });
        System.out.println("按照price 从大到小排序输出：");
        System.out.println(Arrays.toString(books));

        System.out.println("=========================");

        //2.price 从小到大
        Arrays.sort(books, new Comparator() {
            @Override
            public int compare(Object o1, Object o2) {
                Book book1 = (Book) o1;
                Book book2 = (Book) o2;
                double b1 = book1.getPrice();
                double b2 = book2.getPrice();
                if (b1<b2){
                    return -1;
                }else if (b1>b2){
                    return 1;
                }else {
                    return 0;
                }
            }
        });

        System.out.println("按照price 从小到大排序输出：");
        System.out.println(Arrays.toString(books));

        System.out.println("=========================");

        //3.按照书名长度从大到小
        Arrays.sort(books, new Comparator() {
            @Override
            public int compare(Object o1, Object o2) {
                Book book1 = (Book) o1;
                Book book2 = (Book) o2;
                return book2.getBook().length() - book1.getBook().length();
            }
        });

        System.out.println("按照书名长度从大到小排序输出：");
        System.out.println(Arrays.toString(books));



    }
}

class Book{
    private String name;
    private double price;

    public Book(String book, double price) {
        this.name = book;
        this.price = price;
    }

    public String getBook() {
        return name;
    }

    public void setBook(String book) {
        this.name = book;
    }

    public double getPrice() {
        return price;
    }

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

    @Override
    public String toString() {
        return "Book{" +
                "book='" + name + '\'' +
                ", price=" + price +
                '}';
    }
}