Introduction to the "command line processing" framework in the Java class library
Introduction to the "command line processing" framework in the Java class library
Overview:
Command line processing is an important task for processing command line parameters in Java applications.The Java class library provides many command line processing frameworks to simplify the process of analyzing and processing command line parameters.These frameworks provide rich functions, including parsing parameters, verification input, generating help information, etc., and can be scalable and easy to use.
Commonly used command line processing framework:
1. Apache Commons CLI：
Apache Commons Cli is an open source command line parser, which provides rich functions and easy -to -use APIs.It supports the command line options and parameters of the analytical standards, and can automatically generate help information.The following is a simple example:
Options options = new Options();
options.addOption("f", "file", true, "Input file");
CommandLineParser parser = new DefaultParser();
try {
CommandLine cmd = parser.parse(options, args);
String inputFile = cmd.getOptionValue("f");
System.out.println("Input file: " + inputFile);
} catch (ParseException e) {
System.err.println("Error parsing command line arguments");
System.exit(1);
}
2. JCOMAINER:
JCOMMANDER is a simple and powerful command line processing framework, which provides a method of annotating driver to define and parsing the command line parameters.It supports a variety of parameter types, and has a good error processing mechanism and the ability to automatically generate help information.The following is an example:
public class MyApp {
@Parameter(names = "-f", description = "Input file")
private String inputFile;
public static void main(String[] args) {
MyApp app = new MyApp();
JCommander.newBuilder()
.addObject(app)
.build()
.parse(args);
System.out.println("Input file: " + app.inputFile);
}
}
3. Picocli：
PicoCli is another simple and functional command line processing framework, which supports the method of annotation driver to define and analyze the command line parameters.It provides many advanced functions, such as automatic generation usage and help information, automatic completion, parameter verification, etc.The following is an example:
@Command(name = "myapp", description = "MyApp description")
public class MyApp implements Runnable {
@Option(names = {"-f", "--file"}, description = "Input file", required = true)
private String inputFile;
@Override
public void run() {
System.out.println("Input file: " + inputFile);
}
public static void main(String[] args) {
CommandLine.run(new MyApp(), args);
}
}
Summarize:
By using the command line processing framework in the Java library, we can easily analyze and handle the command line parameters, thereby increasing the flexibility and ease of use of the application.Whether it is a simple command line tool or a complex application, these frameworks provide powerful functions and easy -to -use APIs to help us write high -efficiency and easy -to -maintain command line tools.
