AWS SDK で ListDatabases を使用する

    /**
     * Lists all databases asynchronously for the specified cluster, database user, and database.
     * @param clusterId the identifier of the cluster to list databases for
     * @param dbUser the database user to use for the list databases request
     * @param database the database to list databases for
     * @return a {@link CompletableFuture} that completes when the database listing is complete, or throws a {@link RuntimeException} if there was an error
     */
    public CompletableFuture<Void> listAllDatabasesAsync(String clusterId, String dbUser, String database) {
        ListDatabasesRequest databasesRequest = ListDatabasesRequest.builder()
            .clusterIdentifier(clusterId)
            .dbUser(dbUser)
            .database(database)
            .build();

        // Asynchronous paginator for listing databases.
        ListDatabasesPublisher databasesPaginator = getAsyncDataClient().listDatabasesPaginator(databasesRequest);
        CompletableFuture<Void> future = databasesPaginator.subscribe(response -> {
            response.databases().forEach(db -> {
                logger.info("The database name is {} ", db);
            });
        });

        // Return the future for asynchronous handling.
        return future.exceptionally(exception -> {
            throw new RuntimeException("Failed to list databases: " + exception.getMessage(), exception);
        });
    }