Question

我正在使用具有编辑书方法的图书馆应用程序，但目前我遇到了让它做我想做的事的问题。这是我到目前为止所拥有的;

editBook（）方法;

public void editBook(int ID, String title, String author, int quantity, int numOnLoan, int numTimesLoaned)  {
        int i = 0;
        this.myLibrary.get(i).setTitle(title);
        this.myLibrary.get(i).setAuthor(author);
        this.myLibrary.get(i).setQuantity(quantity);
        this.myLibrary.get(i).setNumOnLoan(numOnLoan);
        this.myLibrary.get(i).setNumTimesLoaned(numTimesLoaned);
//The new details of the book are printed out below to confirm the details that the user has entered        
        System.out.println("The new details of this book are: " + "ID: " + this.myLibrary.get(i).getID() + 
                "Title: " + this.myLibrary.get(i).getTitle() + " Author: " + 
        this.myLibrary.get(i).getAuthor() + " Quantity: " + this.myLibrary.get(i).getQuantity() + " No. on Loan: " +
        this.myLibrary.get(i).getNumOnLoan() + " No. of times loaned: " + this.myLibrary.get(i).getNumTimesLoaned());

然后这是switch语句中的代码

case 2: //Edit a Book

            System.out.println("You have chosen to edit a book.");
            System.out.println("Enter the ID of the book you would like to edit: ");
            int ID = sc.nextInt();
            int i = ID;

            System.out.println("You are about to edit: " + mcClay.getBooks().get(i).getTitle() + " by " + 
                    mcClay.getBooks().get(i).getAuthor() );

            System.out.println("Please enter the book's new title: ");
            title = sc.nextLine();
            sc.next();

            System.out.println("Please enter the book's new author: ");
            author = sc.nextLine();
            sc.next();

            System.out.println("How many books do you have?: ");
            while (!sc.hasNextInt()) {
                System.out.println("Enter an integer!");
                sc.nextLine();
                }
            quantity = sc.nextInt();

            System.out.println("How many books currently on loan? (Enter 0 if none): ");
            while (!sc.hasNextInt()) {
                System.out.println("Enter an integer!");
                sc.nextLine();
                }
            numOnLoan = sc.nextInt();

            System.out.println("How many times has this book been loaned out? (Enter 0 if never): ");
            while (!sc.hasNextInt()) {
                System.out.println("Enter an integer!");
                sc.nextLine();
            }
            numTimesLoaned = sc.nextInt();

我用以下输入测试了它，这就是我得到的;

You have chosen to edit a book.
Enter the ID of the book you would like to edit: 
1
You are about to edit: Harry Potter and the Chamber of Secrets by J.K.     Rowling
Please enter the book's new title: 
Harry Potter
Please enter the book's new author: 
J.K Rowling
How many books do you have?: 
Enter an integer!
1
How many books currently on loan? (Enter 0 if none): 
0
How many times has this book been loaned out? (Enter 0 if never): 
0
The new details of this book are: ID: 0Title:  Author:  Potter  Quantity: 1 No. on Loan: 0 No. of times loaned: 0

这显然是错误的，因为没有正确的ID，标题或作者被存储以及＆＃34;数量＆＃34;的输入。即使我没有输入任何内容，也会抛出错误。

我还是编程新手，这让我很困惑。

Answer 1

尝试为Scanner和String创建单独的int。当使用Java Scanner读取多种类型时，它会出现奇怪的行为。

扫描仪行为不当，用户输入

1 个答案: