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 +
'}';
}
}
练习——Arrays类小练
发布时间 2023-03-31 20:37:09作者: Q1uuuu