/**
     * 查询--根据图书名称查询图书信息
     * @param name
     */
    public Book query(String name){
        for (int i = 0; i < list.size(); i++) {
            Book book = list.get(i);
            if (name.equals(book.getName())){
                System.out.println(book);
                return book;
            }
        }
        return null;
    }
 
 
    /**
     * 展示所有图书信息
     */
    public void showAll(){
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }
    }
 
    /**
     * 按照价格降序排序
     */
    public void sort(){
        Collections.sort(list, new Comparator<Book>() {
            @Override
            public int compare(Book o1, Book o2) {
                return -(int)(o1.getPrice()-o1.getPrice());
            }
        });
    }
}