JAVA mongodb 聚合几种查询方式详解

BasicDBObject Query = new BasicDBObject(); 
Query.put("time",new BasicDBObject("$gte", date + " 00:00:00")
 .append("$lte", date + " 23:59:59"));

BasicDBList values = new BasicDBList();
values.add(new BasicDBObject("status", new BasicDBObject("$exists",false)));
values.add(new BasicDBObject("status", 0));
Query.put("$or", values);

DBObject Match = new BasicDBObject("$match", Query);

BasicDBObject GroupBy = new BasicDBObject();// 分组条件
GroupBy.put("userId", "$userId");//根据用户ID来分组

DBObject Select = new BasicDBObject("_id", GroupBy);

Select.put("count", new BasicDBObject("$sum", 1));

DBObject Group = new BasicDBObject("$group", Select);

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);

Iterable<DBObject> map = Output.results();
//遍历map
for (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")));
     
}

import com.mongodb.DBObject; import com.mongodb.util.JSON;

DBObject match = (DBObject) JSON.parse("{$match:{'status':'1','time':
  {$gte:'"+beginDay+"',$lte:'"+endDay+"'}}}");

DBObject group = (DBObject) JSON.parse("{$group:{_id:'$userId', 
  count:{$sum:1},total:{$sum:'$amount'},maxSigle:{$max:'$amount'}}}");

List<DBObject> list = new ArrayList<DBObject>();
list.add(match); list.add(group);
AggregationOutput Output = mongoTemplate.getCollection("表名").aggregate(list);

//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

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);