* java的主要args列表中的含义是什么？

Question

I wrote a class like this and named it Solution.java .

public class Solution {
    public static void main(String[] args) {
        System.out.println(args.length);
    }
}

BUt when I run it in Terminal, I got a result like this:

>  /Users/WangWei  java Solution *
18
>  /Users/WangWei

Why 18?

Answer 1

That's probably the number of files in your working directory.

The result of * is not specific to Java. It is specific to the environment you are working in, ie the working directory and the kind of shell (Windows command prompt, bash, ...) you are using to run the java command. This is because the shell processes and evaluates the command line before starting the process. It replaces the * .

To preserve a * as a command line argument, you need to quote it:

java Solution '*'

Answer 2

你的shell正在解释当前文件夹的内容 - 传入了18个文件。使用单引号来避免解释星号

java Solution '*'

Answer 3

Just add this to your code and you'll see:

for(String line: args)
  System.out.println(line);

Answer 4

The number of files in your directory.

18 shows that 18 files are there in your directory.