Question

我正在尝试创建一个程序，每次用户按下“c”时重新打印文本文件simple.txt，但是使用我的代码，它只会打印一次：

public static void main(String[] args) throws FileNotFoundException {
    Scanner console = new Scanner(System.in);
    Scanner fileSearch = new Scanner(new File("simple.txt"));
    UI(console, fileSearch);
}

public static void UI (Scanner console, Scanner fileSearch) {
    String choice = "Start";
    while (!choice.equals("q")) {
        System.out.print("(C)reate mad-lib, (V)iew mad-lib, (Q)uit? ");
        choice = console.next();
        choice = choice.toLowerCase();
        if (choice.equals("c")) {
            System.out.println("Create");
            CreateMadLibs(fileSearch);
        } else if (!choice.equals("q")) {
            System.out.println("I don't understand.");
        }
    }
}

public static File FileGrab (Scanner fileSearch) {
    File thing = new File(fileSearch.next());
    while (fileSearch.hasNextLine()){
        System.out.println(fileSearch.nextLine());
    }
return thing;
}

public static void CreateMadLibs (Scanner fileSearch) {
    FileGrab(fileSearch);
}

我认为问题是我在main中创建了扫描程序fileSearch而不是UI。我尝试在fileSearch语句中初始化if，但这给了我一个fileNotFoundException。就是这样，我明白了：

Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:862)
    at java.util.Scanner.next(Scanner.java:1371)
    at test.FileGrab(test.java:28)
    at test.CreateMadLibs(test.java:36)
    at test.UI(test.java:20)
    at test.main(test.java:9)

Answer 1

您可以将fileSearch放入while循环，以便每次重新搜索循环时找到file。您只需在UI(console);中致电main。

此外，我建议最后关闭scanner，因为它可能不会再次使用（除非当然重新输入c）。

public static void UI(Scanner console) throws FileNotFoundException {
        String choice = "Start";
        while (!choice.equals("q")) {
            Scanner fileSearch = new Scanner(new File("simple.txt"));
            System.out.print("(C)reate mad-lib, (V)iew mad-lib, (Q)uit? ");
            choice = console.next();
            choice = choice.toLowerCase();
            if (choice.equals("c")) {
                System.out.println("Create");
                CreateMadLibs(fileSearch);
            } else if (!choice.equals("q")) {
                System.out.println("I don't understand.");
            }
            fileSearch.close();
        }
    }

Answer 2

您的代码中有一些功能上无效的行，我建议通过执行以下操作来修改FileGrab方法：

    public static void /*File*/ FileGrab ( Scanner fileSearch ) {
    //File thing = new File(fileSearch.next());  // this line is useless
    while (fileSearch.hasNextLine()){
        System.out.println(fileSearch.nextLine());
    }
    //return thing; // this either
   }

使用扫描仪重复文件打印

2 个答案: