p2e.java

///usr/bin/env jbang "$0" "$@" ; exit $?
//DEPS info.picocli:picocli:4.7.6
//DEPS info.picocli:picocli-codegen:4.7.6
//MANIFEST Implementation-Version=${version:dev}
//JAVA 23

package com.github.helpermethod.p2e;

import java.util.Locale;
import picocli.CommandLine;
import picocli.CommandLine.Command;
import picocli.CommandLine.IVersionProvider;
import picocli.CommandLine.Parameters;
import static java.lang.System.out;

@Command(
    name = "p2e",
    mixinStandardHelpOptions = true,
    versionProvider = p2e.ManifestVersionProvider.class,
    description = "Convert Spring configuration property names to environment variable names."
)
class p2e implements Runnable {
    @Parameters(index = "0", description = "The property name")
    private String property;

    public static void main(String... args) {
        System.exit(new CommandLine(new p2e()).execute(args));
    }

    @Override
    public void run() {
        // see https://docs.spring.io/spring-boot/docs/current/reference/html/features.html#features.external-config.typesafe-configuration-properties.relaxed-binding.environment-variables
        var environmentVariableName =
            property
                .replace(".", "_")
                .replace("-", "")
                .replaceAll("\\[(?<index>[0-9]+)]", "_${index}")
                .toUpperCase(Locale.ENGLISH);

        out.println(environmentVariableName);
    }

    static class ManifestVersionProvider implements IVersionProvider {
        public String[] getVersion() {
            return new String[] { getClass().getPackage().getImplementationVersion() };
        }
    }
}