GridFSFile gridFsdbFile = gridFsTemplate.findOne(new Query(Criteria.where("_id").is(id)));
GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(gridFsdbFile.getObjectId());
GridFsResource gridFsResource = new GridFsResource(gridFsdbFile,gridFSDownloadStream );
então
file.setInputStream(gridFsResource.getInputStream());
Você pode definir gridFSBucket no MongoConfiguration assim
@Bean public GridFSBucket getGridFSBuckets() {
MongoDatabase db = mongoDbFactory().getDb();
return GridFSBuckets.create(db);
}
