Java - 将非原始数据类型文本文件的字符串解析为整数

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已关闭。这个问题是 not reproducible or was caused by typos 。目前不接受答案。

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我试图将文本文件中的字符串转换为非原始数据类型作为整数，但当我尝试解析整数时出现错误

try (Scanner sc = new Scanner(new File(RESOURCE))) {
                    int line_idx = 1;
                    while (sc.hasNextLine()) {
                        String line = sc.nextLine();
                        String[] properties = line.split(SEPARATOR, -1);
                        try {
                            Patron patron = Integer.parseInt(properties[0]);
                            Book book = Integer.parseInt(properties[1]);
                            LocalDate startDate = LocalDate.parse(properties[2]);
                            LocalDate dueDate = LocalDate.parse(properties[3]);
                            Loan loan = new Loan(patron, book, startDate, dueDate);
                            Book.setLoan(loan);
                            Patron.addBook(book);
                        } catch (NumberFormatException ex) {
                            throw new LibraryException("Unable to parse patron id " 
                            + properties[0] + " on line " + line_idx + "\nError: " + ex);
                        }
                        line_idx++;
                    }
                }

            //Loan file
            private Patron patron;
            private Book book;
            private LocalDate startDate;
            private LocalDate dueDate;

            public Loan(Patron patron, Book book, LocalDate startDate, LocalDate dueDate) {
                this.patron = patron;
                this.book = book;
                this.startDate = startDate;
                this.dueDate = dueDate;
            }

    public Book(int id, String title, String author, String publicationYear, String publisher) {
            this.id = id;
            this.title = title;
            this.author = author;
            this.publicationYear = publicationYear;
            this.publisher = publisher;
        }

文本文件:

3::23::2019-09-23::2019-09-30::

错误:

Type mismatch: cannot convert from int to Patron Type mismatch: cannot convert from int to Book

Answer 1

要完成您想要做的事情，您需要为 Book 和 Patron 制作一个构造函数

public class Book{
    public Book(int i){
        //what to do whith the int 
    }
}

然后你就这样调用它

Book book = new Book(Integer.parseInt(properties[1]));