Introduction and comparison of command line processing frameworks commonly used in the Java class library
Introduction and comparison of command line processing frameworks commonly used in the Java class library
When developing Java applications, command lines are a common way of interaction.To implement the analysis and processing of command line parameters, developers can use some commonly used Java libraries.This article will introduce several commonly used command line processing frameworks and compare them.
1. Apache Commons CLI
Apache Commons Cli is a popular Java command line parameter processing framework.It provides a set of simple and easy -to -use APIs for analysis and processing command line parameters.Using Apache Commons Cli, developers can define options, parameters, help information, etc., and analyze it through the command line parser.The following is an example of using Apache Commons Cli:
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");
CommandLineParser parser = new DefaultParser();
HelpFormatter formatter = new HelpFormatter();
try {
CommandLine cmd = parser.parse(options, args);
if (cmd.hasOption("h")) {
formatter.printHelp("myprogram", options);
System.exit(0);
}
} catch (ParseException e) {
System.out.println("Invalid arguments. Use -h or --help for usage.");
System.exit(1);
}
// Make other business processing
}
}
2. JCommander
JCOMMANDER is another popular command line processing framework, which provides an annotation driver to define the command line parameters.JCOMMANDER can automatically analyze the command line parameters based on the defined annotation and pass the results to the corresponding processing method.The following is an example of using JCOMMANDER:
import com.beust.jcommander.JCommander;
import com.beust.jcommander.Parameter;
public class CommandLineParserExample {
@Parameter(names = { "-h", "--help" }, description = "Display help")
private boolean help;
public static void main(String[] args) {
CommandLineParserExample example = new CommandLineParserExample();
JCommander.newBuilder()
.addObject(example)
.build()
.parse(args);
if (example.help) {
JCommander.newBuilder()
.addObject(example)
.build()
.usage();
System.exit(0);
}
// Make other business processing
}
}
3. picocli
Picocli is an emerging command line processing framework that provides simple and easy -to -use APIs and annotations to resolve the command line parameters.Compared with the previously introduced framework, Picocli has richer features, such as parameter verification and automatic generating help information.The following is an example of using picocli:
import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.Option;
@Command(name = "myprogram", description = "This is a program")
public class CommandLineParserExample implements Runnable {
@Option(names = { "-h", "--help" }, usageHelp = true, description = "Display help")
private boolean help;
public static void main(String[] args) {
CommandLine.run(new CommandLineParserExample(), args);
}
@Override
public void run() {
if (help) {
CommandLine.usage(this, System.out);
System.exit(0);
}
// Make other business processing
}
}
In the above example, we use the annotations provided by Picocli to define the options and parameters, and analyze and processes through the method of `Commandline.run ()`.
The above is the introduction and example of several commonly used Java command line processing frameworks.They have their own characteristics and advantages, and developers can choose the appropriate framework according to their needs to process the command line parameters.Whether it is Apache Commons Cli, JCOMMANDER or Picocli, they can help developers to achieve simple and efficient command -line interaction.
