如何获取命令行Java应用程序的多个源文件

Question

I am writing a command line java application and planning to use a library to parse the command line options. and I want to take multiple file names as input.

For now I have chosen apache commons-cli (1.2). My main method is as follows

public static void main(String[] args) {
    Options options = new Options();
    options.addOption("s", "source", true, "file(s) as input");

    CommandLineParser parser = new GnuParser();
    CommandLine input = null;
    try{
        input = parser.parse(options, args);
    }catch (ParseException e){
        new HelpFormatter().printHelp("Usage: ", options);
        System.exit(1);
    }

    String [] files = null;
    if(input.hasOption("s")){
        files = input.getOptionValues("s");         
    }
 }

Now when I execute the program with arguments "-s /home/keshava/file1 /home/keshava/file2" I get only one file in files array.

I know I can get multiple files by "-s /home/keshava/file1 -s /home/keshava/file2" But I dont want to do that.

Is there a way to specify a value separator in any way? Any other library suggestion is also ok.

Thanks, Keshava

Answer 1

In case anyone is still looking for an answer, you can get multiple values in the array by specifying the maximum number of values for a given option supports using the setArgs() method.

Options options = new Options();
Option option = new Option("s", "source", true, "file(s) as input");
// Let option s take up to 5 arguments
option.setArgs(5);
options.addOption(option);

The setArgs() method also accepts Option.UNLIMITED_VALUES when the maximum number of values does not have a fixed limit.

Answer 2

If using OptionBuilder , the method hasArgs() can be applied to the builder, optionally with the limit. Without no limit specified it will use Option.UNLIMITED_VALUES .

// Unlimited
options.addOption(OptionBuilder.withArgName("file(s)").hasArgs().withLongOpt("files").create("f"));

// Limit to 5
options.addOption(OptionBuilder.withArgName("file(s)").hasArgs(5).withLongOpt("files").create("f"));