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;

    }
}