The principle and function analysis of ‘Typed Command Line Parser’ framework in the Java library

The principle and function analysis of ‘Typed Command Line Parser’ framework in the Java library Introduction: In Java development, the analysis and processing of command line parameters is a common task.In order to simplify this process, many developers choose to use the existing command line parsing framework.One of the popular frameworks is ‘Typed Command Line Parser’, which provides a simple and powerful way to analyze and handle command line parameters. Principles and functions: The core principle of the 'Typed Command Line Parser' framework is to mappore the command line parameters with the Java object by defining the parameter model and using the reflection mechanism.It allows developers to map various parameters (such as options, logos and parameters) to the attributes or methods of the Java object. The following is some of the main functions of the ‘Typed Command Line Parser’ framework: 1. Parameter model definition: Developers can create a Java class to define the parameter model.This type should include the attributes or methods of the command line parameters to be parsed, and use a specific annotation to specify their mapping relationship. 2. Parameter annotation: ‘Typed Command Line Parser’ provide some annotations to specify the mapping relationship of the parameter in the parameter model.For example,@option annotations are used to specify an option parameter,@FLAG annotations are used to specify a logo parameter,@Parameters annotation is used to specify a normal parameter, and so on. 3. Parameter analysis: Once the parameter model and annotation configuration is completed, the "Typed Command Line Parser" framework can process the analysis of the command line parameters.It analyzes the command line parameters and assigned them to the corresponding parameter model attributes or methods. 4. Type conversion and verification: ‘Typed Command Line Parser’ framework has the functions of type conversion and parameter verification.It can automatically convert the command line parameter string to represent the corresponding Java data type and perform type verification.If the parameters are not met for the type requirements or verification rules, the framework will report an error prompt. 5. Help document generation: ‘Typed Command Line Parser’ framework can automatically generate the help document of the command line parameter according to the parameter model.In this way, developers can display it to users in a standard format without manually writing help documents. Related configuration and code: The following is a sample code that shows how to configure and use the "Typed Command Line Parser" framework: import com.beust.jcommander.JCommander; import com.beust.jcommander.Parameter; import com.beust.jcommander.Parameters; @Parameters(commandDescription = "This is a command line parser example") public class CommandLineParserExample { @Parameter(names = {"--name", "-n"}, description = "User name", required = true) private String name; @Parameter(names = {"--age", "-a"}, description = "User age", required = true) private int age; public static void main(String[] args) { CommandLineParserExample example = new CommandLineParserExample(); JCommander commander = JCommander.newBuilder() .addObject(example) .build(); commander.parse(args); System.out.println("Hello " + example.name + "! Your age is " + example.age); } } The above code defines a class called "CommandLineParserexample", which contains the parameter model of parsing.Use the @Parameter annotation to specify the name, description, and whether the parameter is necessary. In the main method, we first created a JCOMMANDER instance to add the parameter model object to it.Then resolve the command line parameters by calling the Commander.parse (ARGS).Finally, we can use the analytical parameter model object for follow -up operation. in conclusion: The ‘Typed Command Line Parser’ framework is a powerful and easy -to -use command line parsing framework.It simplifies the analysis process of command line parameters and provides convenient configuration and operation methods.By using the annotation and reflection mechanism, developers can easily map the command line parameters to the Java object, thereby speeding up the development speed and improved code readability.