Best Practices and Development Tips for CLI Framework in Java Class Libraries
Sharing of Best Practices and Development Techniques for CLI Framework in Java Class Libraries
In Java class libraries, the command-line interface (CLI) is a common way of interacting with class libraries or applications. The CLI framework allows us to better organize and parse command-line parameters, provide helpful information, and implement complex command-line operations. This article will share some best practices and development tips for using the CLI framework in Java class libraries.
1. Choose the appropriate CLI framework
Before using the CLI framework, we need to choose a suitable framework. Apache Commons CLI, picocli, and JCommander are some popular choices. These frameworks provide easy-to-use APIs that can help us handle command line parameters and options.
2. Define command line parameters and options
It is important to define command line parameters and options reasonably when designing CLI applications. We should consider specific application requirements and provide them with necessary parameters. When defining parameters, please ensure that the parameter names and option names are clearly expressed, and provide appropriate default values.
The following is sample code that shows how to use Apache Commons CLI to define command line parameters and options:
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 path");
output.setRequired(true);
options.addOption(output);
3. Parsing and Verifying Command Line Parameters
Once command line parameters and options are defined, we need to use the CLI framework to parse them into easy-to-use data structures. Before parsing, we should verify the validity of command line parameters. We can check for missing parameters, correct data format, etc.
The following is sample code that demonstrates how to use Apache Commons CLI to parse and validate command-line parameters:
CommandLineParser parser = new DefaultParser();
HelpFormatter formatter = new HelpFormatter();
CommandLine cmd;
try {
cmd = parser.parse(options, args);
} catch (ParseException e) {
System.out.println(e.getMessage());
Formatter. printHelp ("command-line tool", options);
System.exit(1);
}
String inputFilePath = cmd.getOptionValue("input");
String outputFilePath = cmd.getOptionValue("output");
4. Provide help documents and usage examples
In order to help users better understand the usage of CLI applications, we should provide help documents and usage examples. This information should provide a detailed description of the meaning, usage, and example commands of command line parameters and options. By providing clear documentation, users can more easily use CLI applications.
The following is sample code that shows how to use Apache Commons CLI to generate help documents:
HelpFormatter formatter = new HelpFormatter();
Formatter. printHelp ("command-line tool", options);
5. Implement command line operations
The CLI framework is not only used to parse and validate command-line parameters, but can also help us implement complex command-line operations. For example, we can define multiple subcommands, each of which performs different operations. Each subcommand can have its own parameters and options. By implementing command line operations, we can provide users with more flexible and powerful functions.
The following is an example code that demonstrates how to use picocli to implement a CLI application with multiple subcommands:
@Command (name="search", description="search command")
public class SearchCommand implements Runnable {
@Option (names={"- k", "-- keyword"}, description="Search keyword", required=true)
private String keyword;
@Override
public void run() {
//Performing search operations
}
}
@Command (name="download", description="Download Command")
public class DownloadCommand implements Runnable {
@Option (names={"- u", "-- URL"}, description="Download Link", required=true)
private String url;
@Override
public void run() {
//Perform download operation
}
}
public static void main(String[] args) {
CommandLine commandLine = new CommandLine(new CommandLineApp());
commandLine.addSubcommand("search", new SearchCommand());
commandLine.addSubcommand("download", new DownloadCommand());
commandLine.execute(args);
}
By following the best practices and development techniques mentioned above, we can better use the CLI framework in Java class libraries. The CLI framework provides powerful features that make command-line applications easier to use and maintain.
