Picocli framework and command line parameter analysis principles in the Java class library
The PICOCLI framework and command line parameters in the Java class library analysis principle
Brief introduction
Picocli is a powerful Java class library for analysis and processing command line parameters.It provides a simple and easy -to -use way to create the command line interface, and it can easily analyze the command line parameters and perform the corresponding operation.This article will introduce the basic principles and usage methods of the Picocli framework, and provide some Java code examples to help readers better understand.
Installation and configuration of the Picocli framework
To use the Picocli framework, we need to add it to the dependency item of the Java project.Picocli dependencies can be added to Maven or Gradle configuration files, and then re -construct the project to download and introduce the picocli library.
The first step of using the Picocli framework in the Java code is to create the main class of a command line application. This class will be responsible for the analysis and execution of the command line parameters.You can then define various command line options and parameters using picocli annotations.
Definition of command line options and parameters
The command line options in picocli use the `@option` annotation definition, which is used to specify the name, description, default value, whether it is necessary, etc.The following is an example:
import picocli.CommandLine;
import picocli.CommandLine.Option;
@CommandLine.Command(name = "MyApp", mixinStandardHelpOptions = true, version = "1.0")
public class MyApp implements Runnable {
@Option(names = {"-h", "--host"}, description = "Server host address")
private String host = "localhost";
// Definition of other options and parameters
// omit other code
public void run() {
// Treatment the command line parameters and execute the corresponding operation logic
}
public static void main(String[] args) {
CommandLine.run(new MyApp(), args);
}
}
In the above example, a command line option is defined using the `@option` annotation to define a command line called` -H` or `-Host` to specify the host address of the server.If the user does not provide the value of the option, use the default value `localhost".
The definition of the command line parameters is similar to the option. The `@parameters` notes with no` names` attributes are used for definition.
Analysis of command line parameters
It is very simple to use the Picocli framework to parse the command line parameters.Just call the `commandline.run () method at the entrance point of the program, and pass the instance and command line parameter array of the main class.`Commandline.run ()` method will automatically analyze the command line parameters and call the corresponding method.
For example, you can run the program in the above example in the following way:
$ java MyApp -h example.com
In this example, the value of the user specifies the value of the `eXample.com" `` example.com "through the command line script.The program will analyze the command line parameters and perform the corresponding operation.
Help document and version information
The PicoCli framework also provides built -in help documents and version information functions. These functions can be very convenient to integrate with applications.In the above example, use the built -in help options with the `mixinstandardhelpoptions = true`.If the user uses the `-H` or`-Help` option in the command line, the help document will be displayed automatically.
In addition, the version information of the application can be defined using the `version` attribute.When the user uses `-v` or`-version` in the command line, the version number of the display program will be displayed.
Summarize
Picocli is a powerful and easy -to -use Java class library for analysis and processing command line parameters.It provides an annotation drive method to define the command line options and parameters, and help developers to easily create the command line interface.This article introduces the basic principles and usage methods of the Picocli framework, and provides a simple Java example to illustrate its application.
By using Picocli, developers can easily analyze and process command line parameters and build command line applications.It is hoped that this article will help readers understand the PICOCLI framework and command line parameter analysis principles.
The Picocli framework and command line parameter analysis principles in the # java class library
## profile
Picocli is a powerful Java class library for analysis and processing command line parameters.It provides a simple and easy -to -use way to create the command line interface, and it can easily analyze the command line parameters and perform the corresponding operation.This article will introduce the basic principles and usage methods of the Picocli framework, and provide some Java code examples to help readers better understand.
## Picocli framework installation and configuration
To use the Picocli framework, we need to add it to the dependency item of the Java project.Picocli dependencies can be added to Maven or Gradle configuration files, and then re -construct the project to download and introduce the picocli library.
The first step of using the Picocli framework in the Java code is to create the main class of a command line application. This class will be responsible for the analysis and execution of the command line parameters.You can then define various command line options and parameters using picocli annotations.
## definition of command line options and parameters
The command line options in picocli use the `@option` annotation definition, which is used to specify the name, description, default value, whether it is necessary, etc.The following is an example:
import picocli.CommandLine;
import picocli.CommandLine.Option;
@CommandLine.Command(name = "MyApp", mixinStandardHelpOptions = true, version = "1.0")
public class MyApp implements Runnable {
@Option(names = {"-h", "--host"}, description = "Server host address")
private String host = "localhost";
// Definition of other options and parameters
// omit other code
public void run() {
// Treatment the command line parameters and execute the corresponding operation logic
}
public static void main(String[] args) {
CommandLine.run(new MyApp(), args);
}
}
In the above example, a command line option is defined using the `@option` annotation to define a command line called` -H` or `-Host` to specify the host address of the server.If the user does not provide the value of the option, use the default value `localhost".
The definition of the command line parameters is similar to the option. The `@parameters` notes with no` names` attributes are used for definition.
## Analysis of command line parameters
It is very simple to use the Picocli framework to parse the command line parameters.Just call the `commandline.run () method at the entrance point of the program, and pass the instance and command line parameter array of the main class.`Commandline.run ()` method will automatically analyze the command line parameters and call the corresponding method.
For example, you can run the program in the above example in the following way:
$ java MyApp -h example.com
In this example, the value of the user specifies the value of the `eXample.com" `` example.com "through the command line script.The program will analyze the command line parameters and perform the corresponding operation.
## Help document and version information
The PicoCli framework also provides built -in help documents and version information functions. These functions can be very convenient to integrate with applications.In the above example, use the built -in help options with the `mixinstandardhelpoptions = true`.If the user uses the `-H` or`-Help` option in the command line, the help document will be displayed automatically.
In addition, the version information of the application can be defined using the `version` attribute.When the user uses `-v` or`-version` in the command line, the version number of the display program will be displayed.
## Summarize
Picocli is a powerful and easy -to -use Java class library for analysis and processing command line parameters.It provides an annotation drive method to define the command line options and parameters, and help developers to easily create the command line interface.This article introduces the basic principles and usage methods of the Picocli framework, and provides a simple Java example to illustrate its application.
By using Picocli, developers can easily analyze and process command line parameters and build command line applications.It is hoped that this article will help readers understand the PICOCLI framework and command line parameter analysis principles.
