How to use the "Typed Command Line Parser" framework in the Java class library to achieve parameter analysis of parameters
How to use the "Typed Command Line Parser" framework in the Java class library to achieve parameter analysis of parameters
In Java development, command line parameters are often required to facilitate users to input and configure some parameters during the program runtime.In actual development, in order to simplify the work of parameter analysis, we can use the "Typed Command Line Parser" framework to help us complete the task of parameter analysis.
The ‘Typed Command Line Parser’ framework can help us define the command line parameter structure of the expected command line, and automatically analyze the command line parameters, and convert them into the corresponding data type for program use.The following will introduce you to how to use this framework to implement parameter analysis.
First, we need to introduce the dependence of the "Typed Command Line Parser" framework in the project.The introduction can be completed by adding corresponding dependencies (such as Maven's pom.xml file) to the project construction file.The following is an example dependencies:
<dependency>
<groupId>net.sourceforge.argparse4j</groupId>
<artifactId>argparse4j</artifactId>
<version>0.9.0</version>
</dependency>
Once we introduce the dependence of the framework, we can start writing code to achieve parameter analysis.
First, we need to define a parameter parser.You can create a class, such as `ArgumentParserSerutil`, and use the` Argumentparsers.newFor (String) `to create a parameter parser instance:
import net.sourceforge.argparse4j.ArgumentParsers;
import net.sourceforge.argparse4j.inf.ArgumentParser;
public class ArgumentParserUtil {
public static ArgumentParser createArgumentParser(String description) {
return ArgumentParsers.newFor("MyProgram").description(description).build();
}
}
Next, we can add the parameters of the parameter parser to add the parameters we expect parsing.The following is an example code:
import net.sourceforge.argparse4j.inf.ArgumentParser;
public class ArgumentParserUtil {
public static ArgumentParser createArgumentParser(String description) {
ArgumentParser parser = ArgumentParsers.newFor("MyProgram").description(description).build();
parser.addArgument("-n", "--name")
.dest("name")
.type(String.class)
.required(true)
.help("Name of the user");
parser.addArgument("-a", "--age")
.dest("age")
.type(Integer.class)
.required(false)
.setDefault(18)
.help("Age of the user");
return parser;
}
}
In the above code, we define two parameters: one is `name` and the other is` age`.By calling the `adDARGUMENT" method, we can specify the names, data types, and whether the data type, and whether the parameter must be.For example, `Type (String.class)` means that the data type of the parameter is a string, and `Required (TRUE)` means that the parameters are necessary.
After we define the parameter parser, we can use the following code to analyze the command line parameters:
import net.sourceforge.argparse4j.inf.ArgumentParser;
import net.sourceforge.argparse4j.inf.Namespace;
import net.sourceforge.argparse4j.internal.ArgumentParserImpl;
public class MyApp {
public static void main(String[] args) {
ArgumentParser parser = ArgumentParserUtil.createArgumentParser("My Program");
Namespace ns = ((ArgumentParserImpl) parser).parseArgsOrFail(args);
String name = ns.getString("name");
int age = ns.getInt("age");
System.out.println("Name: " + name);
System.out.println("Age: " + age);
}
}
In the above code, we first call the `Createargumentparser` method to create a parameter parser, and then call the` PAREARGSORFAIL` method to analyze the command line parameters, and save the resolution in the `namespace` object.Finally, we can obtain the values of each parameter through the method of `GetString` and` Getint`.
When the user runs the program in the command line, they can use the following commands to pass the parameters:
java MyApp -n Alice -a 25
In the above command, `-n` represents the` name` parameter, `-a` represents the` age` parameter, and the values in the back are the actual values of the parameter.
The above is a simple example of using the "Typed Command Line Parser" framework to implement parameter analysis.Through this framework, we can easily define the parameter structure of the expectations and automatically analyze the command line parameters.In this way, we can handle the command line parameters more efficiently to improve the availability and user experience of the program.
