mongo大数据量查询优化

mongo in查询数量较多时

时间对比：

4W条数据查询速度达到3-4S

优化后可以达到0.1S-0.2S

优化原理：mongo自动Bean转化功能性能较差，改用原生mongo游标方法读取MongoDB数据文档，并在内存中做bean转化

优化前

Query query = new Query();

queryAfter.addCriteria(Criteria.where("id").in(idList));
queryAfter.addCriteria(Criteria.where("time").gte(startTime).lte(endTime));
List<TestEntity> lists = mongoTemplate.find(queryBefore,TestEntity.class);

 优化后

DBObject query1 = new BasicDBObject(); //setup the query criteria 设置查询条件
 query1.put("id", new BasicDBObject("$in", idList));
 query1.put("time", (new BasicDBObject("$gte", startTime)).append("$lte", endTime));
 DBCursor dbCursor =mongoTemplate.getCollection("testEntity").find(query1);
 List<TestEntity> list=new ArrayList<>();
 while (dbCursor.hasNext()){
 DBObject object=dbCursor.next();
 TestEntity te=new TestEntity();
 te.setId(object.get("_id").toString());
 te.setTime((Date) object.get("time"));
 list.add(te); 
}