The comparison and selection guide of the "command line parameter parser" in the Java class library and other parsers
The comparison and selection guide of the "command line parameter parser" in the Java class library and other parsers
When developing Java applications, obtaining and parsing command line parameters is a common task.To simplify this process, many Java libraries provide different "command line parameter parser" frameworks.This article will compare the characteristics of these frameworks and provide guidelines for choosing a suitable parser.
1. Apache Commons CLI:
Apache Commons Cli is a widely used command line parameter parser with rich characteristics and flexible usage.The following are some of the main features:
-Profile label options (for example: -v, --Verbose) and location parameters.
-In extensive option verification and error handling mechanism.
-The built -in help information generator can automatically generate help documents for applications.
Below is an example of using Apache Commons Cli to analyze the command line parameters:
import org.apache.commons.cli.*;
public class CommandLineParserExample {
public static void main(String[] args) {
Options options = new Options();
options.addOption("h", "help", false, "Display help information");
options.addOption("v", "verbose", false, "Enable verbose mode");
CommandLineParser parser = new DefaultParser();
try {
CommandLine cmd = parser.parse(options, args);
if (cmd.hasOption("h")) {
// Display help information
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp("myapp", options);
}
if (cmd.hasOption("v")) {
// Enable detailed mode
System.out.println("Verbose mode enabled");
}
} catch (ParseException e) {
// Parameter analysis error
System.err.println("Error parsing command line arguments: " + e.getMessage());
}
}
}
2. JCommander:
JCOMMANDER is a lightweight command line parameter parser, which provides a simple statement and friendly wrong prompts.The following are some of the main features:
-In the annotation to declare the command line options and parameters, simplify the code.
-In support the nested object model, which can analyze the more complex command line structure.
-The ability to convert a custom type conversion, which can easily convert the parameters into a target type.
The following is an example of using JCOMMANDER to analyze the command line parameters:
import com.beust.jcommander.*;
public class CommandLineParserExample {
public static void main(String[] args) {
Args argsobj = new args (); // Define objects containing parameters
JCommander.newBuilder().addObject(argsObj).build().parse(args);
if (argsObj.help) {
// Display help information
JCommander.newBuilder().addObject(argsObj).build().usage();
}
if (argsObj.verbose) {
// Enable detailed mode
System.out.println("Verbose mode enabled");
}
}
private static class Args {
@Parameter(names = {"-h", "--help"}, help = true)
private boolean help;
@Parameter(names = {"-v", "--verbose"})
private boolean verbose;
}
}
3. Picocli:
Picocli is another popular command line parameter parser, which has simple API and rich features.The following are some of the main features:
-In the way to support multiple command line options, including annotations and programming APIs.
-It can automatically generate help information and complete prompts.
-Colid the typical Unix -style command line parameters, such as the sub -commands, parameter arrays and option groups.
The following is an example of using picocli to parse the command line parameters:
import picocli.CommandLine.*;
@Command(name = "myapp", mixinStandardHelpOptions = true)
public class CommandLineParserExample implements Runnable {
@Option(names = {"-v", "--verbose"}, description = "Enable verbose mode")
private boolean verbose;
public void run() {
if (verbose) {
// Enable detailed mode
System.out.println("Verbose mode enabled");
}
}
public static void main(String[] args) {
CommandLine.run(new CommandLineParserExample(), args);
}
}
According to the above comparison and characteristics, the following is some guidelines for choosing command line parameters:
-If you need a flexible and fully functional parser, you can choose Apache Commons Cli.It is very useful for processing various parameter types and complex parameter structures, and at the same time provides a comprehensive error processing and help information generation mechanism.
-If you need a simple, statement, and easy -to -use parser, you can choose JCOMMANDER.Its annotation method can simplify the parameter declaration, and it is very easy to integrate into the existing code.
-If you need a parser that supports the UNIX -style command line parameters, and you want to automatically generate help information and complete prompts, you can choose Picocli.It provides rich characteristics and is very easy to use and integrated.
In summary, select the appropriate command line parameter parser depends on your needs and preferences.According to the scale, complexity and characteristics of the project, the most suitable parser can be greatly improved, which can greatly improve development efficiency and code readability.
