如何在Java中实现从文本到对象的转换

Question

public void loadFromFile() {
    System.out.println("Loading books...");
    FileInputStream fileInput = null;
    try {
        fileInput = new FileInputStream("books.txt");
        Scanner sc = new Scanner(fileInput);
        if (sc.hasNext()) {
            System.out.format("%-5s %-45s %-10s", "Id", "Name", "Price");
            System.out.println();
            while (sc.hasNextLine()) {

                System.out.println(sc.nextLine());

            }
        } else {
            System.out.println("(empty)");
        }

    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        System.err.println("File not found");
    } finally {
        try {
            fileInput.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    // TODO: your code here
}

我有一个。txt文件，要求一个程序读取它并将其解析为Object。每一行都是一个对象，包括属性id、name和price

如何将文本解析为对象

Answer 1

public static final class Book {

    private int id;
    private String name;
    private double price;

}

public static void main(String... args) throws FileNotFoundException {
    List<Book> books = readMovies(new File("a.txt"));
}

private static List<Book> readMovies(File file) throws FileNotFoundException {
    try (Scanner scan = new Scanner(file)) {
        scan.useLocale(Locale.ENGLISH);

        List<Book> books = new ArrayList<>();

        while (scan.hasNext()) {
            Book book = new Book();
            book.id = scan.nextInt();

            String line = scan.nextLine().trim();
            int pos = line.indexOf("  ");
            book.name = line.substring(0, pos).trim();
            book.price = Double.parseDouble(line.substring(pos + 1).trim());
            books.add(book);
        }

        return books;
    }
}