@PostMapping("/meta/saveOrUpdate")
    public Mono<String> saveOrUpdate(@RequestBody final MetaData metaData) {
        if (CollectionUtils.isEmpty(subscribers)) {
            return Mono.just(Constants.SUCCESS);
        }
        LOG.info("saveOrUpdate apache shenyu local meta data");
        subscribers.forEach(metaDataSubscriber -> metaDataSubscriber.onSubscribe(metaData));
        return Mono.just(Constants.SUCCESS);
    }
Save or update mono.

@param metaData the meta data
@return the mono
shenyu-web/src/main/java/org/apache/shenyu/web/controller/LocalMetadataController.java