用java实现有Book类，并定义书籍若干本，信息如下所示，请定义一个 成类，有属性成员(author, name,price) 请定义成员的方法和构造方法等方法，请编程实现便得书籍按价格降序输出，

好的，以下是用Java实现这个需求的代码：

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

class Book {
    private String author;
    private String name;
    private double price;

    public Book(String author, String name, double price) {
        this.author = author;
        this.name = name;
        this.price = price;
    }

    public String getAuthor() {
        return author;
    }

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }

    @Override
    public String toString() {
        return author + ": " + name + " - " + price;
    }
}

class Bookstore {
    private List<Book> books;

    public Bookstore(List<Book> books) {
        this.books = books;
    }

    public void displayBooksByPrice() {
        Collections.sort(books, new Comparator<Book>() {
            @Override
            public int compare(Book b1, Book b2) {
                return Double.compare(b2.getPrice(), b1.getPrice());
            }
        });
        for (Book book : books) {
            System.out.println(book);
        }
    }
}

public class Main {
    public static void main(String[] args) {
        List<Book> books = new ArrayList<>();
        books.add(new Book("J.K. Rowling", "Harry Potter and the Philosopher's Stone", 35.5));
        books.add(new Book("J.R.R. Tolkien", "The Lord of the Rings", 89.9));
        books.add(new Book("George Orwell", "Animal Farm", 19.9));
        books.add(new Book("Harper Lee", "To Kill a Mockingbird", 28.5));
        Bookstore bookstore = new Bookstore(books);
        bookstore.displayBooksByPrice();
    }
}

输出结果为：

J.R.R. Tolkien: The Lord of the Rings - 89.9
J.K. Rowling: Harry Potter and the Philosopher's Stone - 35.5
Harper Lee: To Kill a Mockingbird - 28.5
George Orwell: Animal Farm - 19.9

以上代码中，我们定义了一个 `Book` 类和一个 `Bookstore` 类。`Book` 类有三个属性成员 `author`，`name` 和 `price`，还有一个构造方法。`Bookstore` 类有一个属性成员 `books` 和一个方法 `displayBooksByPrice`，该方法按照价格降序输出所有书籍。在测试代码中，我们创建了一些书籍，并将它们传递给 `Bookstore` 对象，然后调用 `displayBooksByPrice` 方法输出结果。