[JAVA]如何在特定数组中添加元素

Question

我正在尝试用 java 中的数组创建一个示例，我想创建一个图书馆，其中包含一些按类别排序的书籍，我想使用 addBook 方法将书籍添加到类别数组中，但我没有如果我有很多数组，我不知道该怎么做，目标是将书添加到相同的类别外壳中，我将 3 个类称为 Estante,Libros,libreria。

package com.manzacatesSAS;

/**
 * Created by deborah on 7/09/16.
 */
public class Libreria    
{   
    Estante[] miedo     = new Estante[6];
    Estante[] comedia   = new Estante[6];
    Estante[] novelas   = new Estante[6];
    Estante[] romance   = new Estante[6];
    Estante[] comics    = new Estante[6];    
}

 package com.manzacatesSAS;   

/**
 * Created by deborah on 7/09/16.
 */
public class Estante {

    //attributes of Estante
    private int maxNumLibros = 6;
    //I guess this isn't necesay because if i use array,this only has 6 spaces
    private int maxPages = 3000;
    private String categoria = "";
    private int currentLibros = 0;
    private int currentPages = 0;

    public int getNumLibros() {
        return maxNumLibros;
    }

    public void setNumLibros(int maxNumLibros) {
        this.maxNumLibros = maxNumLibros;
    }

    public int getMaxPages() {
        return maxPages;
    }

    public void setMaxPages(int maxPages) {
        this.maxPages = maxPages;
    }

    public String getCategoria() {
        return categoria;
    }

    public void setCategoria(String categoria) {
        this.categoria = categoria;
    }

    /**
     * Constructor de Estantes
     *
     * @param categoria categoria de los libros
     */
    //No añadi los parametros restantes dado que al crear uno nuevo sus atributos deben estar vacios, o definidos por los atributos comunes.
    public Estante(String categoria) {
        this.categoria = categoria;
    }

        public void addBook(Libros x){
            if (currentPages + x.getNumPages() < maxPages && currentLibros < maxNumLibros) {
                currentLibros++;
            //I guess the array of the categorie to add the book would be here, and i think that use a for to add the book in the correct array.
            }
        }
    }

Answer 1

请参阅下面的类设计（如果您将类放在单独的文件中，请将它们设为public）。

在您的主程序中，您可以执行以下操作：

Library library = new Library();
Shelf shelf1 = new Shelf("Shelf 1");
library.addShelfToLibrary(shelf1);
Category fiction = new Category("fiction");
Category literature = new Category("literature");
Book book1 = new Book("Don Quixote");
book1.addBookToCategory(fiction);     // category for this book
book1.addBookToCategory(literature);  // another category for same book
shelf1.addBookToShelf(book1);

这是课程设计。您将需要添加更多方法，这是一个骨架。

class Library {
    private ArrayList<Shelf> shelves = new ArrayList<>();

    public void addShelfToLibrary(Shelf shelf) {
        if (!this.shelves.contains(shelf)) {
            this.shelves.add(shelf);
        }
    }
}

class Category {
    private String catname;

    public Category(String catname) {
        this.catname = catname;
    }

    public String getCatname() {
        return catname;
    }
}

class Book {
    private String title;
    private ArrayList<Category> categories = new ArrayList<>();

    public Book(String title) {
        this.title = title;
    }

    public ArrayList<Category> getCategories() {
        return categories;
    }
    public void addBookToCategory(Category category) {
        if (!this.categories.contains(category)) {
            this.categories.add(category);
        }
    }
}

class Shelf {
    private String shelfId;
    private ArrayList<Book> booksOnShelf = new ArrayList<>();

    public Shelf(String shelfId) {
        this.shelfId = shelfId;
    }

    public void addBookToShelf(Book book) {
        if (!this.booksOnShelf.contains(book)) {
            this.booksOnShelf.add(book);
        }
    }
}