Apache Common CLI:如何添加参数? [英] Apache Common CLI: How to add arguments?

问题描述

我将通用 CLI 用于个人项目.我没有从文档中找到的一件事是如何强制某个论点呈现.

I am using the Common CLI for a personal project. One thing I didn't find from the documentation is that how to enforce a certain argument to present.

为了澄清我的问题，我可以定义参数和选项之间的不同，命令:

To clarify my question, can I define the different between argument and option, the command:

    mycommand file.txt -b 2

mycommand is the command, 
file.txt is the argument
-b 2 is the option where 2 is the option value

使用 Common CLI，我可以添加 -b 2 作为这样的选项:

With Common CLI, I can add -b 2 as an option like this:

    options.addOption( "b", true, "Some message" );

并使用以下方法解析参数:

And parse the arguments using:

CommandLineParser commandParser = new GnuParser();
CommandLine result = commandParser.parse(options, args)

但是如何指定 file.txt 也是必需的?

but how can I specify file.txt is also required?

非常感谢

推荐答案

我没有意识到您的意思是将目标(不是选项)设为必需.

I didn't realize you meant make the target (not an option) to be required.

如果您使用完整的解析方法CommandLineParser.parse(Options, String[], boolean) 并将可选标志设置为 false，那么解析器将跳过未知参数.

If you use the full parse methodCommandLineParser.parse(Options, String[], boolean) with the optional flag set to false, then the parser will skip over unknown arguments.

您可以稍后通过返回 String[]

You can later retrieve them by the method getArgs() which returns a String[]

然后您可以检查这些字符串以确保有一个名为 file.txt 的字符串

You can then go through those Strings to make sure there is a string called file.txt

Options options = new Options();

options.addOption("b", true, "some message");

String[] myArgs = new String[]{"-b","2", "file.txt"};
CommandLineParser commandParser = new GnuParser();

CommandLine commandline = commandParser.parse(options, myArgs, false);

System.out.println(Arrays.toString(commandline.getArgs()));

将[file.txt]打印到屏幕上.

所以你添加一个额外的检查来搜索该数组以找到任何需要的目标:

so you add an extra check to search through that array to find any required targets:

boolean found=false;
for(String unparsedTargets : commandline.getArgs()){
    if("file.txt".equals(unparsedTargets)){
        found =true;
    }
}
if(!found){
    throw new IllegalArgumentException("must provide a file.txt");
}

我同意这很混乱，但我不认为 CLI 提供了一种干净的方法来做到这一点.

I agree it's messy but I don't think CLI provides a clean way to do this.

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