How Can I Parse Command-Line Arguments in Java?

Parsing Command Line Arguments in Java

Parsing command line arguments in Java allows you to pass values to your program when it's executed, providing a flexible way to configure and customize its behavior.

Available Libraries:

For a robust and feature-rich solution, consider using the following libraries:

• Apache Commons CLI: http://commons.apache.org/cli/
• JSAP: http://www.martiansoftware.com/jsap/

Custom Implementation Using the Scanner Class:

If you prefer to roll your own solution, you can utilize the Scanner class from the Java API to read input arguments: http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html

Example Using Commons CLI to Parse String Arguments:

The following code snippet demonstrates how to use Commons CLI to parse two string arguments:

import org.apache.commons.cli.*;

public class Main {

    public static void main(String[] args) throws Exception {

        Options options = new Options();

        Option input = new Option("i", "input", true, "input file path");
        input.setRequired(true);
        options.addOption(input);

        Option output = new Option("o", "output", true, "output file");
        output.setRequired(true);
        options.addOption(output);

        CommandLineParser parser = new DefaultParser();
        HelpFormatter formatter = new HelpFormatter();
        CommandLine cmd = parser.parse(options, args);

        String inputFilePath = cmd.getOptionValue("input");
        String outputFilePath = cmd.getOptionValue("output");

        System.out.println(inputFilePath);
        System.out.println(outputFilePath);

    }

}

Command Line Usage:

You can execute the program in the following way:

$> java -jar target/my-utility.jar -i asd
Missing required option: o

usage: utility-name
 -i,--input <arg>    input file path
 -o,--output <arg>   output file

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