从Jshell运行回送示例

Question

我读过这样一个命令行参数示例：

public class Echo {
    public static void main (String[] args) {
        for (String s: args) {
            System.out.println(s);
        }
    }
}

它从命令行正确运行，我如何从Jshell运行它？

jshell> Echo.main testing
|  created variable testing, however, it cannot be referenced until class main is declared

它报告未能被引用的错误。

Answer 1

您可以像任何其他静态方法一样调用它：

Echo.main(new String[] { "hello", "world" });

整届会议：

$ jshell
|  Welcome to JShell -- Version 11.0.8
|  For an introduction type: /help intro

jshell> public class Echo {
   ...>     public static void main (String[] args) {
   ...>         for (String s: args) {
   ...>             System.out.println(s);
   ...>         }
   ...>     }
   ...> }
|  created class Echo

jshell> Echo.main(new String[] { "hello", "world" });
hello
world

注意，您可以如下所示声明您的main方法：

public static void main(String... args) { ... }

这是与String[] args语法兼容的二进制文件，但允许您按以下方式调用它：

Echo.main("hello", "world");