只需在= new Scanner（System中使用 public static final Scanner .in）; 在您的 main 类中。
之后，您可以通过 MainClassName.in 在任何地方调用它。

Simply use public static final Scanner in = new Scanner(System.in); in you main class. After that you can call it from anywhere by MainClassName.in.

另外，请注意您传递给Scanner的参数。我想您想将 InputFile 放入 Scanner 而不是 filename =）

Also, be careful with arguments you pass to Scanner. I guess you wanted to put InputFile into Scanner, rather than filename =)

File InputFile = new File (filename);
Scanner reader = new Scanner(filename);