How to use Mongo with Spring Data without ObjectId

Question

I have an existing mongo database in which ids (_id) are persisted as plain Strings.. This is sample data in Mongo DB:

{
    \"_id\" : \"528bb0e2e4b0442f1479         


        

Answer 1

I think the problem here is a wrong "_id" format and that is why Mongo cannot recognize any object with such id. It should looks like ObjectId("528bb0e2e4b0442f1479f1b4"), not plain String type.

        {
            "_id" : ObjectId("528bb0e2e4b0442f1479f1b4"),
            "schoolId" : "URDLKYLFJXLWJGR193778316742298",
            "surname" : "Lewis",
            "admissionNumber" : "0347",
            "firstName" : "Martins"
        }

So if you have imported .json with existing data to mongo you need to change id:

"_id": {$oid:"528bb0e2e4b0442f1479f1b4"},

And it should be converted to correct format.

Hope it can help someone.