如何使用 maven 编写一个小型、完整的 Annotation Processor 示例？

问：

我需要实现一个 Annotation Processor，它生成一个与带注释的类相关的 Java 类。然而，我目前最大的挑战是了解如何使用 Maven 实现这样一个注解处理器并使其工作。

注解如下：

@Retention(RetentionPolicy.CLASS)
@Target(ElementType.TYPE)
public @interface Tag {
    String value() default "";
}

处理器是这样的：

@SupportedAnnotationTypes({"Tag"})
@SupportedSourceVersion(SourceVersion.RELEASE_11)
public class TagProcessor extends AbstractProcessor {
    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
        for (TypeElement annotation : annotations) {
            var annotatedElements = roundEnv.getElementsAnnotatedWith(annotation);
            for (var element : annotatedElements) {
                if (element.getKind() == ElementKind.CLASS) {
                    var className = ((TypeElement) element).getQualifiedName().toString();
                    var packageName = className.substring(0, className.lastIndexOf('.'));
                    var simpleClassName = className.substring(className.lastIndexOf('.') + 1);
                    var infoClassName = simpleClassName + "Info";
                    var tagValue = element.getAnnotation(Tag.class).value();

                    // Generate the source code for the new class
                    var infoClassSource = generateInfoClass(packageName, infoClassName, tagValue);

                    // Write the generated source code to a new file
                    try {
                        writeSourceFile(packageName, infoClassName, infoClassSource);
                    } catch (IOException e) {
                        processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR,
                                "Error generating " + infoClassName + ": " + e.getMessage());
                    }
                }
            }
        }
        return true;
    }

    private String generateInfoClass(String packageName, String infoClassName, String tagValue) {
        return "package " + packageName + ";\n\n" +
                "public class " + infoClassName + " {\n" +
                "    private String tag = \"" + tagValue + "\";\n\n" +
                "    public String getTag() {\n" +
                "        return tag;\n" +
                "    }\n" +
                "}";
    }

    private void writeSourceFile(String packageName, String className, String source) throws IOException {
        var filer = processingEnv.getFiler();
        var fileObject = filer.createSourceFile(packageName + "." + className);
        try (var writer = fileObject.openWriter()) {
            writer.write(source);
        }
    }
}