Question

我需要使用主要方法中的数组，并转移到我的 getBook方法中， 然后将新创建的对象返回到main方法中的数组。

我决定将阵列转移到下一个方法，方法与使用扫描仪相同，直到扫描仪出错时需要调用该方法为止。

public class BookShopApplication 
{

    public static void main(String[] args) 
    {
        Scanner kybd = new Scanner (System.in);
        Book [] books = new Book [10];

        for (int i = 0; i > books.length; i++) 
        {
            books[i] = getBook(kybd, Book books[])
        }

    }

    public static Book[] getBook(Scanner kybd, Book books[]) 
    {


        System.out.println("What is the title of the next book?");
        String readTitle = kybd.nextLine();

        System.out.println("What is thr title of thje next book?");
        String readAuthor = kybd.nextLine();

        if (readAuthor == null)
        {
            for (int i = 0; i < books.length; i++)
            {
                books[i] = new Book();
                books[i].Book(readTitle);
            }

        }
        else 
        {
             for (int i = 0; i < books.length; i++)
            {
                books[i] = new Book();

                books[i].Book(readAuthor, readTitle);


            }

        }
    return books;
    }
}

我需要的结果是将书返回数组并存储。

Answer 1

假设您的Book类看起来与此类似：

class Book
{
    private String title;
    private String author;

    public void setTitle(String title)
    {
        this.title = title;
    }

    public void setAuthor(String author)
    {
        this.author = author;
    }
}

更有意义的是，您尝试分别实例化书籍并将它们存储在Book对象的数组中。

public static void main(String[] args) {

    Scanner kybd = new Scanner (System.in);
    Book [] books = new Book [10];

    // < is needed not >
    for (int i = 0; i < books.length; i++) 
    {
        // book[] is empty, it has an index of 10 with no nodes
        // You need to create the instance to pass into the method
        books[i] = getBook(kybd, new Book());
    }
}

// This should only take the book it is working with
public static Book getBook(Scanner kybd, Book book)
{
    System.out.println("What is the title of the next book?");
    String readTitle = kybd.nextLine();

    System.out.println("What is the title of the next book?");
    String readAuthor = kybd.nextLine();

    if (!readAuthor.isEmpty())
    {
        book.setTitle(readTitle);
    }

    if(!readTitle.isEmpty())
    {
        book.setAuthor(readAuthor);
    }

    return book;
}

您还有很多语法错误，而且-使用.isEmpty()方法而不是使用=== null。

更新：您实际上从未在循环中创建Book的实例。另外，for (int i = 0; i > books.length; i++)-应该是<而不是>。

此代码现在应该可以工作。

Answer 2

好吧，您确实有一些语法错误：

首先，在您的for循环中，books[i] = getBook(kybd, Book books[])应替换为books[i] = getBook(kybd, books)（要将变量作为参数传递给方法，只需使用其名称即可！）

第二，在方法签名中，将public static Book[] getBook(Scanner kybd, Book books[])替换为public static Book[] getBook(Scanner kybd, Book[] books) （请注意，它是Book[] books，而不是Book books[]）。

希望这会有所帮助！

而且，正如Jaquarh所说，您缺少分号！

编辑：此外，您的方法getBooks应该返回一本书，而不是Jaquarh指出的数组。否则，线 books[i] = getBook(kybd, Book books[])将崩溃。

Answer 3

for (int i = 0; i > books.length; i++) 
    {
        books[i] = getBook(kybd,books);
    }

应该做到这一点，而不会引起错误

这也是无效的：

  for (int i = 0; i < books.length; i++)
        {
            books[i] = new Book();
            **books[i].Book(readTitle);**
        }

    }
    else 
    {
         for (int i = 0; i < books.length; i++)
        {
            books[i] = new Book();

            **books[i].Book(readAuthor, readTitle);**

已编辑

如何将对象数组从一种方法转换为另一种方法并返回一个新对象？

3 个答案: