6-23 sdust-Java-可实现多种排序的Book类 (20 分)

6-23 sdust-Java-可实现多种排序的Book类 (20 分)

设计Book类，要求：1）Book类的成员属性包括：书名name（String类型）、出版日期publishDate（Date类型）、定价price（double型）；2）为Book对象提供按出版日期、价格排序的两种方式，且能够满足测试程序代码中的输入输出要求（注意代码注释中的说明）。其中，类BookComparatorByPrice的排序功能是：将一组Book对象按照价格升序排序，如果价格相同，则按照书名字母顺序排列；类BookComparatorByPubDate的排序功能是：将一组Book对象按照出版日期降序排序。

裁判测试程序样例：

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		Book[] books = new Book[4];
		//1. 从键盘接收用户输入的4本书的名称（仅有英文字符构成）、出版日期（格式：1998-10-09）、价格，生成Book对象，构造包含4本书的数组
		for(int i=0;i<4;i++){
			String name = scan.next();
			String date_str = scan.next();
			Date date = null;
			//将键盘录入的日期字符串转换为Date
			SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
			try {
				date = sdf.parse(date_str);
			} catch (ParseException e) {
				System.out.println("日期格式有误");;
			}
			
			double price = Double.parseDouble(scan.next());
			
			Book book = new Book(name, date, price);
			books[i] = book;
		}
		
		//2.将books按照出版日期降序排序；然后输出books
		Arrays.sort(books, new BookComparatorByPubDate());
		for(Book book:books){
			System.out.println(book);
		}
		
		//3.将books按照价格升序排序，如果价格相同，则按照书名字母顺序排列。然后输出books
		Arrays.sort(books, new BookComparatorByPrice());
		for(Book book:books){
			System.out.println(book);
		}
		
		scan.close();
	}

}

/* 请在这里填写答案 */

输入样例：

Java
2011-08-01
29
Python
2014-01-01
48
C
2004-09-08
17.5
DataBase
2012-09-17
17.5

输出样例：

书名:Python,定价:48.0
书名:DataBase,定价:17.5
书名:Java,定价:29.0
书名:C,定价:17.5
书名:C,定价:17.5
书名:DataBase,定价:17.5
书名:Java,定价:29.0
书名:Python,定价:48.0

AC代码:

class Book
{
    public String name;
    public double price;
    public Date publishDate;
    public Book(){}
    public Book(String name,Date date,double price)
    {
        this.name = name; this.publishDate = date;
        this.price = price;
    }


    @Override
    public String toString()
    {
        return "书名:" + name +",定价:" + price;
    }
}

class BookComparatorByPubDate implements Comparator
{
    public int compare(Object o1,Object o2)
    {
        Book book1 = (Book) o1;
        Book book2 = (Book)o2;
        return -(book1.publishDate.compareTo(book2.publishDate));
    }
}

class BookComparatorByPrice implements Comparator
{
    public int compare(Object o1,Object o2)
    {
        Book book1 = (Book)o1;
        Book book2 = (Book)o2;
        if(book1.price == book2.price)
        {
            return book1.name.compareTo(book2.name);
        }
        else
        {
            if(book1.price - book2.price > 0)
            {
                return 1;
            }
            return -1;
        }
    }
}