Java:对象数组中的对象数组

Question

我正在构建一个库程序，它有4个类：

• Books ==>包含一本书的标题
• 体裁==>包含一个体裁的名称和一个对象数组
• Library ==>包含一个体裁的对象数组
• ==>包含对话框和扫描器

您将能够从app类创建新的类型数组和新的图书数组。

public class App{
  Library library = new Library();

  //the other stuff

  private void run(){
     library.addGenres(insertGenreNameHere);
  }
}


public class Library{
   private Genres[] genres = new Genres[5];    //Obj. Array of genres
   private Int nrOfGenres = 0;                 //number of how many genres there are in an array

    public void addGenres(String genreName){   //adds a new genre to the array
       if (nrOfGenres < genres.length) {
        genres[nrOfGenres] = new Genres(genreName);
        nrOfGenres++;
    }
    else {
        System.out.println("You already have the maximum of " + genres.length + " genres!");
    }
}



public class Genres {

   private String name;
   private Books[] books = new Books[5];        //Obj. Array of books
   private int nrOfBooks = 0;                   //number of how many books there are in an array

   public Genres(String name) {                 //Constructor
       this.name = name;
   }

   //getter & setter for the name of the genre

   public void addBooks(String titel){          //adds new book to the array
      if (nrOfBooks < books.length) {
         books[nrOfBooks] = new Books(titel);
         nrOfBooks++;
    }
    else {
        System.out.println("You already have the maximum of " + books.length + " books!");
    }
}

public void showBooks(){                        //prints the books line by line
    int x = 0;
    while(x < books.length && books[x] != null) {
        System.out.println(books[x].getTitle());
        x++;
    }
  }
}



public class Books(){
   private String title;

   public Books(String title){                  //Constructor
      this.title = title;
   }

   //getter & setter for the title
}

然而，我还不知道如何将一本书添加到它的体裁中，甚至不知道我应该如何“联系”(？)书

，如果我是正确的，我不能只做流派=新类型()；或图书=新图书()；，因为它必须在数组(？)

如果有人能帮我，我会很高兴的，如果需要的话，我很乐意分享更多的信息。

干杯马丁

Answer 1

你确定书的数量和类型的数量都是不变的吗？我认为将书籍和类型从数组转换为ArrayList应该有助于您实现程序的顺利运行。你不需要统计书籍的数量和类型的数量。当您使用ArrayList及其size()方法时，事情可能要简单得多。