How to Add Custom Command Line Options and Arguments in Java Class Libraries Using CLI Framework
How to add custom command-line options and parameters using the CLI framework in Java class libraries
Introduction:
When developing Java class libraries, sometimes it is necessary to add command line options and parameters to the class library, so that users can configure and execute the functions of the class library through the command line. The CLI (Command Line Interface) is a convenient framework that can be used to handle command line options and parameters. This article will introduce how to use the CLI framework to add custom command-line options and parameters to Java class libraries.
Step 1: Add dependencies for the CLI framework
Firstly, we need to add a dependency on the CLI framework in the Java class library project. In the Maven project, the following dependencies can be added to the pom.xml file:
<dependency>
<groupId>commons-cli</groupId>
<artifactId>commons-cli</artifactId>
<version>1.4</version>
</dependency>
Step 2: Create command line options and parameters
Next, we need to define the command-line options and parameters for the class library. You can use the Options class provided by the CLI framework to create command-line options. For example, we need to add a command line option called "input" to the class library and set its description to "input file path". You can create this command-line option using the following code:
import org.apache.commons.cli.Option;
import org.apache.commons.cli.Options;
public class MyLibraryOptions {
public static Options createOptions() {
Options options = new Options();
Option input=new Option ("input", true, "input file path");
options.addOption(input);
//Add more command-line options
return options;
}
}
Step 3: Parse command line parameters
Next, we need to parse the command line parameters and execute the corresponding logic based on the user's input. You can use the CommandLineParser class provided by the CLI framework to parse command line parameters. The following is an example code that demonstrates how to parse the "input" parameter in command line options:
import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.ParseException;
public class MyLibrary {
public static void main(String[] args) {
Options options = MyLibraryOptions.createOptions();
CommandLineParser parser = new DefaultParser();
try {
CommandLine commandLine = parser.parse(options, args);
String input = commandLine.getOptionValue("input");
//Execute the logic of the class library based on input
} catch (ParseException e) {
//Handling parsing exceptions
}
}
}
Step 4: Execute class library logic
After parsing the command line parameters, we can execute the corresponding logic of the class library based on user input. For example, files can be read and processed based on the input path specified by the user. The following is an example code:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class MyLibrary {
public static void main(String[] args) {
Options options = MyLibraryOptions.createOptions();
CommandLineParser parser = new DefaultParser();
try {
CommandLine commandLine = parser.parse(options, args);
String input = commandLine.getOptionValue("input");
//Read input file
try (BufferedReader reader = new BufferedReader(new FileReader(input))) {
String line;
while ((line = reader.readLine()) != null) {
//Process each row of data
}
} catch (IOException e) {
//Handling file read exceptions
}
} catch (ParseException e) {
//Handling parsing exceptions
}
}
}
Conclusion:
By using the CLI framework, we can easily add custom command-line options and parameters to the Java class library, and execute corresponding logic based on user input. The above is the process of adding custom command-line options and parameters to the Java class library using the CLI framework. I hope this article is helpful to you!
