Java中的Comparable<T>接口

package org.lyk.entities;
 

public class Book implements Comparable<Book>
{
    static int totalCount;
    private String title;
    @Override
    public String toString()
    {
        return "Book [title=" + title + ", price=" + price + "]";
    }

    private float price; 
    
    public Book(){}

    public Book(String title, float price)
    {
        super();
        this.title = title;
        this.price = price; 
    }  
    
    @Override
    public int compareTo(Book o)
    {
//        private String title;
//        private float price;
//        private String category;
//        private Author author;
        
        if(this.price < o.price)
            return -1;
        else if(this.price > o.price)
            return 1;
        
        if(this.title.compareTo(o.title) != 0)
            return this.title.compareTo(o.title);
        
        
        return 0;
    }
 

}

package org.lyk.main;

import org.lyk.entities.Book;

public class Main
{ 
    public static void main(String[] args)
    {
        Book[] books = new Book[]
                {
                        new Book("Java", 85),
                        new Book("Oracle", 99),
                        new Book("Html5", 85),
                        new Book("JSP", 64),
                        new Book("Servlet", 99)
                };
        java.util.Arrays.sort(books);
        for(Book item : books)
        {
            System.out.println(item);
        }
        
        System.out.println(("" instanceof String));
    }
}