1.自定义图书类

package lianxiti;

public class Book {

    private String title;
    private String author;
    private double price;
    
    public Book(String title,String author,double price){
        
        this.title=title;
        
        this.author=author;
        
        this.price=price;
    }
    public String getTitle(){
        return title;
    }
    public String getAuthor(){
        return author;
    }
    public double getPrice(){
        return price;
        
    }
}