编写 mongodb 文档时如何忽略 _id 和 _class？

Question

I have one collection which stores time-series data, only insert and query, no update and delete, as MongoTemplate genenrates _id and _class fields automatically, these two fields consume disk space and I don't need them, how can I ignore them when writing?

PS: I know how to ignore _class globally, how to ignore _class only for one specific collection?

Answer 1

I'm not sure why you would want to enable the global _class & _id and disable it only certain conditions.

Anyway for the problem, if you want to discard those fields, you can just convert your POJO to a raw json and directly save it in Mongo.

Document document = Document.parse(jsonString)
mongoTemplate.getCollection("collection").insertOne(document);

You can create a wrapper write method to incorporate these changes.