项目用的MongoDB要改为分布式的，有人说程序里有用到group统计的要改代码，集群环境下不支持。代码如下
DBObject _match = new BasicDBObject();
_match.put("MAIN_TAG","0");
_aggregate.add(new BasicDBObject("$match", _match));
DBObject _group = new BasicDBObject();
DBObject _id = new BasicDBObject();
_id.put("SUPER_ID", "$SUPER_ID");
_group.put("_id", _id);
_group.put("COUNT", new BasicDBObject("$sum", 1));
_aggregate.add(new BasicDBObject("$group", _group));
AggregationOutput output = mongodbTemplate.getDB("xxx").getCollection("xxxxx").aggregate(_aggregate);