我正在使用Spring框架对我的mongodb执行聚合。但是，查找一直失败，我不明白为什么。这是查询:Aggregationaggregation=newAggregation(match(Criteria.where("idOfUser").is(loggedInAccount.getId())),group("imgID"),newCustomAggregationOperation(newBasicDBObject("$lookup",newBasicDBObject("from","img").append("localField","_id").append("foreign