Export hibernate ddl changes to flyway db migrations in spring mvc or spring boot

HibernateDDLFlywayMigration.java

@Slf4j
@Component
@Profile("exportDDL")
@org.springframework.context.annotation.Configuration
class HibernateDDLFlywayMigration {

  @Bean ExportDDLExecutor exportDDLExecutor(Environment environment, Flyway flyway, EntityManagerFactory factory){
    return new ExportDDLExecutor(environment, flyway, factory)
  }

  static class ExportDDLExecutor {
    ExportDDLExecutor(Environment environment, Flyway flyway, EntityManagerFactory factory) throws Exception {
      if (factory.unwrap(SessionFactoryImpl.class) == null) {
        throw new NullPointerException("factory is not a hibernate factory");
      }
      SessionFactoryImpl hibernateFactory = factory.unwrap(SessionFactoryImpl.class);


      Dialect dialect = hibernateFactory.dialect
      Configuration config = hibernateFactory.serviceRegistry.@configuration
      DatabaseMetadata meta = new DatabaseMetadata(flyway.dataSource.getConnection(), dialect, config);
      List<SchemaUpdateScript> schemaUpdates = config.generateSchemaUpdateScriptList(dialect, meta)

      MigrationInfo last = null;

      if (flyway.info().all() && flyway.info().all().size() > 0) {
        last = flyway.info().all().last()
      }

      int nextIndex = last ? Integer.parseInt(last.version.toString()) + 1 : 1

      if (!schemaUpdates) {
        log.info("no schema updates detected")
      }

      for (SchemaUpdateScript update : schemaUpdates) {
        if (last && last.script && (update.script == last.script)) {
          continue
        }

        String migrationFile = "src/main/resources/db/migration/V${nextIndex}__${generateDescription(update.script)}.sql"
        log.info("creating migration @${migrationFile} \n" + update.script)
        new File(migrationFile).write(update.script + ";")
        println update.script
        ++nextIndex
      }

      if (environment.acceptsProfiles("applyDDL")) {
        log.info("applying schema migrations where applicable")
        flyway.migrate()
      }
    }

    static String generateDescription(String sql) {
      if (sql.startsWith("SELECT")) {
        return "DML";
      } else {
        return "DDL";
      }
    }
  }

}