Java中如何將文本轉換為物件

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
}

我有一個 .txt 檔案，要求程式讀取它并將其決議為物件。每行是一個物件，包括屬性 id、名稱和價格

如何將文本決議為物件

uj5u.com熱心網友回復：

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;
    }
}

uj5u.com熱心網友回復：

// 這段代碼可以幫到你，樂于助人

匯入 java.io.*; 公共類 FileTextCheck {

public static void main(String[] args) {

    User u1 = new User("Sudhakar", 27, "Male");
    User u2 = new User("Richa", 25, "Female");

    try {
        FileOutputStream fos = new FileOutputStream(new File("/home/orange/Desktop/myfile.txt"));
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(u1);
        oos.writeObject(u2);
        oos.close();
        fos.close();

        FileInputStream fis = new FileInputStream(new File("/home/orange/Desktop/myfile.txt"));
        ObjectInputStream ois = new ObjectInputStream(fis);

        User pr1 = (User) ois.readObject();
        User pr2 = (User) ois.readObject();

        System.out.println(pr1.toString());
        System.out.println(pr2.toString());

        ois.close();
        fis.close();

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

}

public static class User implements Serializable {
    private static final long serialVersionUID = 1L;
    private String name;
    private int age;
    private String gender;

    User(String name, int age, String gender) {
        this.name = name;
        this.age = age;
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "Name:"   name   "\nAge: "   age   "\nGender: "   gender;
    }
}

}

uj5u.com熱心網友回復：

您不能將任何型別的文本決議為 java 物件。文本應為 JSON 格式。您可以使用Gson庫將JSON 字串決議為 java 物件。

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