Question

我有这种方法，我试图从文本文件读入，然后将其中的内容添加到我的数组，我的方法似乎没问题，但是当我朗读程序时，我在屏幕上显示 null 请帮助我的代码。

    File text = new File("C:\\Users\\Stephen\\Desktop\\CA2\\src\\Management_System_Package\\GAMES.txt");
    Scanner scnr = new Scanner(text);

    String GameLine;
    GameLine = scnr.nextLine();

    while (scnr.hasNextLine()) {

        Management_System Game = new Management_System("", "", 0, 0, 0);

        int Comma1 = GameLine.indexOf(", ");
        String Title = GameLine.substring(0, Comma1).trim();
        Game.setTitle(Title);

        System.out.print(Title);

        int Comma2 = GameLine.indexOf(", ", Comma1 + 1 );
        String Genre = GameLine.substring(Comma1 + 1, Comma2);
        Game.setGenre(Genre);

        int Comma3 = GameLine.indexOf(", ", Comma2 + 1 );
        String ID = GameLine.substring(Comma2 + 1, Comma3);
        Game.setID(Double.parseDouble(ID));

        int Comma4 = GameLine.indexOf(", ", Comma3 + 1 );
        String Rating = GameLine.substring(Comma3 + 1, Comma4);
        Game.setRating(Integer.parseInt(Rating));

        String Quantity = GameLine.substring(Comma4 + 1).trim();
        Game.setQuantity(Integer.parseInt(Quantity));

        add(Game);

        GameLine = in.nextLine();

Answer 1

这是因为您的代码有一个错误，您从循环中读取一行，并且您将始终跳过文件的最后一行。如果您的文件只有一行，则scnr.hasNextLine()将为false，并且不会运行while循环。

我认为split()是获取所需字符串和整数的更好方法。像这样的代码：

String GameLine;

while (scnr.hasNextLine()) {
    GameLine = scnr.nextLine();
    Management_System Game = new Management_System("", "", 0, 0, 0);
    String[] tags = GameLine.split(",");

    Game.setTitle(tags[0]);

    Game.setGenre(tags[1]);

    Game.setID(Double.parseDouble(tags[2]));

    Game.setRating(Integer.parseInt(tags[3]));

    Game.setQuantity(Integer.parseInt(tags[4]));

    add(Game);
}

Java从文本文件中读取（字符串和整数）

1 个答案: