How can I convert a Stream of Mono to Flux

Answer 1

Probably, what you need is the following:

@GetMapping("getMatches")
public Flux<Object> getMatches(@RequestParam String matchesId) {
    List<Long> matchesList = JSON.parseArray(matchesId, Long.class);
    return Flux.fromStream(matchesList.stream())
               .flatMap(this::getMatch);
}

Instead of:

@GetMapping("getMatches")
public Flux<Object> getMatches(@RequestParam String matchesId) {
    List<Long> matchesList = JSON.parseArray(matchesId, Long.class);
    return Flux.fromStream(matchesList.parallelStream().map(this::getMatch));
}

Notes:

• Basically, you expect getMatches endpoint to return Flux<Object>. However, as it is written - it actually returns Flux<Mono<Object>>, therefore you see the strange output. To get Flux<Object>, I suggest, first, create Flux<Long> that are match ids, and then flatMap the result of calling getMatch (that returns Mono<Object>), this finally gives Flux<Object>.

• Also, there is no need to use parallelStream(). Because you're already using reactor, everything will be performed concurrently on reactor scheduler.