How to make new mono with DTO from mono and flux in spring reactive webflux

Question

Here I try to make call from database and combine into new mono from different mono and flux.

public Mono<ListMovieWithKomenDTO> fetchMovieAndKomen(Integer movieId){
            Mono<Movie> movie = findById(movieId).subscribeOn(Schedulers.elastic());
            Flux<MovieKomen> movieKomen = getKomenByMovieId(movieId).subscribeOn(Schedulers.elastic());
            return Mono.zip(movie, movieKomen.collectList(), movieMovieKomenDTOBiFunction);
        }

private BiFunction<Movie, List<MovieKomen>, ListMovieWithKomenDTO> movieMovieKomenDTOBiFunction = (x1, x2) -> ListMovieWithKomenDTO.builder()
                // .age(x1.getAge())
                .id(x1.getId())
                .name(x1.getName())
                .status(x1.getStatus())
                .detail(x1.getDetail())
                .url(x1.getUrl())
                .movieKomen(x2).build();

In here I make db call twice for header ( like movie ) and detail ( like movie comment ) to separate them. After I make retrieve two different data, I want to join into new mono data based on flux data and mono. to make them into one data, I make DTO to put together from movie table and comment table but it failed. I assume that errors from mono.zip to get data into one new mono.

Here the error from debug console

java.lang.IllegalArgumentException: Cannot encode parameter of type org.springframework.r2dbc.core.Parameter
    at io.r2dbc.postgresql.ExtendedQueryPostgresqlStatement.bind(ExtendedQueryPostgresqlStatement.java:89) ~[r2dbc-postgresql-0.8.10.RELEASE.jar:0.8.10.RELEASE]

Thank you

Answer 1

Problem is in my repository I used

public interface MovieKomenRepository  extends ReactiveCrudRepository<MovieKomen,Integer> {
    @Query("select * from m_movie_komen where m_movie_id = $1")
    Flux<MovieKomen> findByMovieId(int movie_id);
}

in above example, I used $1 for the param in query. But when I change my code like bottom. It works like a charm.

public interface MovieKomenRepository  extends ReactiveCrudRepository<MovieKomen,Integer> {
    @Query("select * from m_movie_komen where m_movie_id = :movie")
    Flux<MovieKomen> findByMovieId(@Param("movie") int movie_id);
}

so if someone want to use my service code is fine but careful in repository. we should not used '$1' instead ':movie'. so the problem not in service or mono/flux. but in my repository

Thank you.