方法里面的方法 [英] Methods inside methods

问题描述

在Java中使用main方法中的方法在语法上是否正确？例如

Is it syntactically correct to have a method inside the main method in Java? For example

class Blastoff {

    public static void main(String[] args) {

        //countdown method inside main
        public static void countdown(int n) {

            if (n == 0) {
                System.out.println("Blastoff!");
            } else {
                System.out.println(n);
                countdown(n - 1);
            }
        }
    }
}

推荐答案

不，不是直接;但是，方法可能包含本地内部类，当然内部类可以包含方法。 这个StackOverflow问题给出了一些例子。

No, not directly; however, it is possible for a method to contain a local inner class, and of course that inner class can contain methods. This StackOverflow question gives some examples of that.

在你的但是，你可能只想从 main 里面调用倒计时;你实际上并不需要它的整个定义在 main 里面。例如：

In your case, however, you probably just want to call countdown from inside main; you don't actually need its entire definition to be inside main. For example:

class Blastoff {

    public static void main(String[] args) {
        countdown(Integer.parseInt(args[0]));
    }

    private static void countdown(int n) {
        if (n == 0) {
            System.out.println("Blastoff!");
        } else {
            System.out.println(n);
            countdown(n - 1);
        }
    }
}

（请注意，我是声明倒计时为 private ，因此只能在 Blastoff中调用 class，我假设你的意图是什么？）

(Note that I've declared countdown as private, so that it can only be called from within the Blastoff class, which I'm assuming was your intent?)

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