mongodb的聚合查询 Java代码 www.2cto.com MongoClient mongoClient = null; try { mongoClient = new MongoClient(102.198.119.29, 27017); DB db = mongoClient.getDB(syslog); //设置Where条件 DBObject match = new BasicDBObject($match, new BasicDBOb mongodb的聚合查询Java代码 www.2cto.com MongoClient mongoClient = null;try {mongoClient = new MongoClient("102.198.119.29", 27017);DB db = mongoClient.getDB("syslog");//设置Where条件DBObject match = new BasicDBObject("$match", new BasicDBObject("DATE",(new BasicDBObject("$gt", "2012-11-28 00:19:00")).append("$lt", "2012-11-29 09:19:00")));//设置分组字段BasicDBObject groupFilters = new BasicDBObject("_id", "$PRIORITY");//对分组字段统计行数MongoDB For Windows v3.5.4 MongoDB For Windows v3.5.4下载groupFilters.put("count", new BasicDBObject("$sum", 1));BasicDBObject group = new BasicDBObject("$group", groupFilters);//设置显示的字段集合DBObject fields = new BasicDBObject("PRIORITY", 1);fields.put("_id", "$PRIORITY");DBObject project = new BasicDBObject("$project", fields);AggregationOutput output = db.getCollection("messages").aggregate(match, project, group);System.out.println(output.getCommandResult());} catch (UnknownHostException e) {e.printStackTrace();}
MongoDB的聚合查询
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