AND、OR和IN操作
AND:public void testAnd(){      //agender='female' AND age > 27        DBObject queryCondition = new BasicDBObject();      queryCondition.put("agender", "female");      queryCondition.put("age", new BasicDBObject("$gt", 27));      DBCursor dbCursor = coll.find(queryCondition);      assertEquals(1, dbCursor.size());      assertEquals("Jane", dbCursor.next().get("username"));  }  OR:public void testOrSingleField(){      DBObject queryCondition = new BasicDBObject();            //age<15 OR age>27      queryCondition = new BasicDBObject();      BasicDBList values = new BasicDBList();      values.add(new BasicDBObject("age", new BasicDBObject("$gt", 27)));      values.add(new BasicDBObject("age", new BasicDBObject("$lt", 15)));      queryCondition.put("$or", values);      DBCursor dbCursor = coll.find(queryCondition);      assertEquals(3, dbCursor.size());      assertEquals("tom", dbCursor.next().get("username"));  }  OR:public void testOrMultiFields(){      DBObject queryCondition = new BasicDBObject();            //agender=female OR age<=23      queryCondition = new BasicDBObject();      BasicDBList values = new BasicDBList();      values.add(new BasicDBObject("agender", "female"));      values.add(new BasicDBObject("age", new BasicDBObject("$lte", 23)));      queryCondition.put("$or", values);      DBCursor dbCursor = coll.find(queryCondition);      assertEquals(4, dbCursor.size());      assertEquals("Jim", dbCursor.next().get("username"));  }IN:public void testIn(){      DBObject queryCondition = new BasicDBObject();            //age in [13, 47]      queryCondition = new BasicDBObject();      BasicDBList values = new BasicDBList();      values.add(13);      values.add(47);      queryCondition.put("age", new BasicDBObject("$in", values));      DBCursor dbCursor = coll.find(queryCondition);      assertEquals(2, dbCursor.size());      assertEquals("tom", dbCursor.next().get("username"));  }
JAVA mongodb 聚合几种查询方式详解
https://www.jb51.net/article/137196.htm一、BasicDBObject整个聚合查询是统计用户的各种状态下的用户数量为场景:1.筛选条件:date为查询日期:BasicDBObject Query = new BasicDBObject(); Query.put("time",new BasicDBObject("$gte", date + " 00:00:00") .append("$lte", date + " 23:59:59"));如果有多个条件:直接加Query.put("status", 0);如果有OR筛选:BasicDBList values = new BasicDBList();values.add(new BasicDBObject("status", new BasicDBObject("$exists",false)));values.add(new BasicDBObject("status", 0));Query.put("$or", values);其中 new BasicDBObject("$exists",false)) 就是“status”不存在(mongodb文档可不等于实体的字段)2.拼接matchDBObject Match = new BasicDBObject("$match", Query);将上一步的Query放入macth筛选中3.拼接分组条件此步相当于SQL的Group ByBasicDBObject GroupBy = new BasicDBObject();// 分组条件GroupBy.put("userId", "$userId");//根据用户ID来分组同第一步的筛选一样,如果有多个分组可直接添加在后面:GroupBy.put("status", "$status");4.分组后查询首先把分组拼接上:DBObject Select = new BasicDBObject("_id", GroupBy);如果我们要对分组后的数据进行操作:(这里是用户的统计数量)Select.put("count", new BasicDBObject("$sum", 1));5.拼接$groupDBObject Group = new BasicDBObject("$group", Select);至此。我们拼接,mongodb的语句到此结束下面我们开始查询操作:import com.mongodb.AggregationOutput;import org.springframework.data.mongodb.core.MongoTemplate;AggregationOutput Output = mongoTemplate.getCollection("这里是mongodb的数据表名")  .aggregate(Match, Group);读取查询结果:Iterable<DBObject> map = Output.results();//遍历mapfor (DBObject dbObject : map) {  //这里读取到的map为{"_id":{"userId":1,"status"0}}...     Map<String, Object> resultMap = (Map<String, Object>) dbObject.get("_id");  //这里截取掉.0     Integer userId = Integer.parseInt(CommUtil.toString(ausgMap.get("userId")).replace(".0",""));  //在这里我们就可以对我们的数据进行操作了;    Integer count = Integer.parseInt(CommUtil.toString(dbObject.get("count")));}二、DBObject不多说,如果大家觉得第一种方法特别长篇大论,那么下面我给大家带来一种代码更简洁的聚合查询:直接上代码吧。1.注意导入的包:import com.mongodb.DBObject; import com.mongodb.util.JSON;2.$macth:(beginDay-查询开始日期;endDay-查询结束日期)DBObject match = (DBObject) JSON.parse("{$match:{'status':'1','time':  {$gte:'"+beginDay+"',$lte:'"+endDay+"'}}}");3.$group:(以userId分组,统计用户数量,累加amout字段值,取amout字段最大值)DBObject group = (DBObject) JSON.parse("{$group:{_id:'$userId',   count:{$sum:1},total:{$sum:'$amount'},maxSigle:{$max:'$amount'}}}");条件拼接完,开始查询:List<DBObject> list = new ArrayList<DBObject>();list.add(match); list.add(group);AggregationOutput Output = mongoTemplate.getCollection("表名").aggregate(list);遍历结果就不用在说了。上面已经详细描述了第二种方法是不是比一种方式简单多了。但是比较考验自身对mongodb语句熟悉性。【扩展】接着上面的方法进行扩展//status 为0或者为1 ; type 不为11;time在beginDay ~ endDay时间段内DBObject match = (DBObject) JSON.parse("{$match:{'status':{$in:['0','1']},  type:{$ne:11},'time':{$gte:'"+beginDay+"',$lte:'"+endDay+"'}}}");//以用户Id分组,统计查询次数,取最后一次time的时间DBObject group = (DBObject) JSON.parse("{$group:{_id:'$userId',   count:{$sum:1},lastTime:{$max:'$time'} }}");//在上一步统计出的结果中筛选次数大于100的数据DBObject groupMatch = (DBObject) JSON.parse("{$match:{count:{$gte:100}}}");//$project----查询结果中需要显示哪些字段,显示则设置为1。如下需要不显示_id 域(字段),则需如下指定://db.集合名.aggregate( [ { $project : { _id: 0, count: 1 , lastSuccTime: 1 } } ] )DBObject project = (DBObject) JSON.parse("{$project:{_id:1,count:1,lastSuccTime:1}}");DBObject sort = (DBObject) JSON.parse("{$sort:{'count':-1}}");//排序List<DBObject> list = new ArrayList<DBObject>();list.add(match);list.add(group);list.add(groupMatch);list.add(project);list.add(sort);AggregationOutput catchOutPut = mongoTemplate.getCollection("表名")  .aggregate(list);//查询结果三、BasicDBObject+脚本语句BasicDBObject groupIndex = new BasicDBObject();BasicDBObject distinctQuery = new BasicDBObject();distinctQuery.put("userId", new BasicDBObject("$in", userIds));//UserIds数组BasicDBObject initIndex = new BasicDBObject();initIndex.put("count", 0);//给count赋初值// 脚本(doc代表数据库的数据.prev代表查询结果//prev.count这里的count就是上一步initIndex的count)String reduce = "function(doc, prev) {if(doc.status==0){prev.count+= 1;};}";List<Map<String, Object>> basicDBList = (List<Map<String, Object>>) mongoTemplate.  getCollection("Collection").group(groupIndex, distinctQuery, initIndex, reduce, null);最后循环遍历List即可得到结果【PS:group这种聚合方式有个限制条件--->超过20000数据就会报错】以上就是我在普通业务处理中用到mongodb聚合处理