您可以将 ArrayList 作为命令行参数传递给 Java 程序吗

Question

I am attempting to pass as input to a java program via a command line argument an ArrayList of BigIntegers.

I understand calling a program as such:

java myProgram one two

args[0] = "one"
args[1] = "two"

But if I was to run the program as such

java myProgram arrayList 

How would I convert the String[] representation of this Arraylist back to an ArrayList<BigInteger>

The arrayList will be returned from a separate java file that returns an arrayList of BigInetegr, could I use that java program as an input to this one?

I am a little confused as how I would go about this.

Thanks!

Answer 1

As long as you are passing actual decimal strings to your program, eg java myProgram 123 456 .

List<BigInteger> bigInts = new ArrayList<>(args.length);
for(int i = 0; i < args.length; i++)
    bigInts.add(new BigInteger(args[i]));

Or using Java 8 streams:

List<BigInteger> bigInts = Arrays.stream(args)
                            .map(BigInteger::new)
                            .collect(Collectors.toList());

But if you're passing words to your program, then two things, you will need a custom function to parse English words to BigInteger , plus I doubt anyone will be typing out an integer large enough require a BigInteger .